diff --git a/.github/workflows/check-PRs.yml b/.github/workflows/check-PRs.yml
index 112ba5da3..bec3595ec 100644
--- a/.github/workflows/check-PRs.yml
+++ b/.github/workflows/check-PRs.yml
@@ -132,6 +132,52 @@ jobs:
           name: ganache-test-logs
           path: ./ganache-test.log
 
+  optimist-sync-test:
+    runs-on: ubuntu-18.04
+    steps:
+      - uses: actions/checkout@master
+      - uses: actions/setup-node@v1
+        with:
+          node-version: '14.17.0'
+
+      - name: Start Containers
+        run: |
+          ./setup-nightfall
+          ./start-nightfall -g -d &> optimist-sync-test.log &disown
+
+      - name: Wait for images to be ready
+        uses: Wandalen/wretry.action@v1.0.11
+        with:
+          command: |
+            docker wait nightfall_3_deployer_1
+          attempt_limit: 100
+          attempt_delay: 20000
+
+      - name: Debug logs - after image builds
+        if: always()
+        run: cat optimist-sync-test.log
+
+      - name: Run optimist sync test
+        run: |
+          npm ci
+          docker wait nightfall_3_deployer_1
+          npm run test-optimist-sync
+
+      - name: Debug logs - after optimist sync test run
+        if: always()
+        run: cat optimist-sync-test.log
+
+      - name: If optimist sync test failed, shutdown the Containers
+        if: failure()
+        run: docker-compose -f docker-compose.yml -f docker-compose.ganache.yml down -v
+
+      - name: If optimist sync test failed, upload logs files as artifacts
+        if: failure()
+        uses: actions/upload-artifact@master
+        with:
+          name: optimist-sync-test-logs
+          path: ./optimist-sync-test.log
+
   adversary-test:
     runs-on: ubuntu-20.04
     env:
@@ -149,7 +195,7 @@ jobs:
         run: |
           ./setup-nightfall
           ./geth-standalone -s
-          sleep 300 
+          sleep 300
           ./start-nightfall -l -d -a &> adversary-test.log &disown
 
       - name: Wait for images to be ready
@@ -175,7 +221,7 @@ jobs:
       - name: If integration test failed, shutdown the Containers
         if: failure()
         run: |
-          docker-compose -f docker-compose.yml -f docker-compose.dev.yml -f docker-compose.ganache.yml -f docker-compose.adversary.yml down -v 
+          docker-compose -f docker-compose.yml -f docker-compose.dev.yml -f docker-compose.ganache.yml -f docker-compose.adversary.yml down -v
           ./geth-standalone -d
 
       - name: If integration test failed, upload logs files as artifacts
diff --git a/cli/lib/environment.mjs b/cli/lib/environment.mjs
index eafa921c2..19a26364c 100644
--- a/cli/lib/environment.mjs
+++ b/cli/lib/environment.mjs
@@ -11,9 +11,9 @@ const SUPPORTED_ENVIRONMENTS = {
   ropsten: {
     name: 'Ropsten',
     chainId: 3,
-    clientApiUrl: 'https://client1.testnet.nightfall3.com',
-    optimistApiUrl: 'https://optimist1.testnet.nightfall3.com',
-    optimistWsUrl: 'wss://optimist1-ws.testnet.nightfall3.com',
+    clientApiUrl: 'https://client.testnet.nightfall3.com',
+    optimistApiUrl: 'https://optimist.testnet.nightfall3.com',
+    optimistWsUrl: 'wss://optimist-ws.testnet.nightfall3.com',
     web3WsUrl: 'wss://ropsten1-ws.testnet.nightfall3.com',
   },
   rinkeby: {
@@ -35,10 +35,10 @@ const SUPPORTED_ENVIRONMENTS = {
   docker: {
     name: 'Docker',
     chainId: 1337,
-    clientApiUrl: 'http://client1',
-    optimistApiUrl: 'http://optimist1',
-    optimistWsUrl: 'ws://optimist1:8080',
-    web3WsUrl: 'ws://blockchain1:8546',
+    clientApiUrl: 'http://client',
+    optimistApiUrl: 'http://optimist',
+    optimistWsUrl: 'ws://optimist:8080',
+    web3WsUrl: 'ws://blockchain:8546',
   },
 };
 
diff --git a/cli/lib/nf3.mjs b/cli/lib/nf3.mjs
index fec0ad183..75e56599c 100644
--- a/cli/lib/nf3.mjs
+++ b/cli/lib/nf3.mjs
@@ -219,7 +219,7 @@ class Nf3 {
         data: unsignedTransaction,
       });
     } catch (error) {
-      logger.warn(`estimateGas failed. Falling back to constant value`);
+      // logger.warn(`estimateGas failed. Falling back to constant value`);
       gasLimit = GAS; // backup if estimateGas failed
     }
     return Math.ceil(Number(gasLimit) * GAS_MULTIPLIER); // 50% seems a more than reasonable buffer.
@@ -232,11 +232,11 @@ class Nf3 {
       const res = (await axios.get(GAS_ESTIMATE_ENDPOINT)).data.result;
       proposedGasPrice = Number(res?.ProposeGasPrice) * 10 ** 9;
     } catch (error) {
-      logger.warn('Gas Estimation Failed, using previous block gasPrice');
+      // logger.warn('Gas Estimation Failed, using previous block gasPrice');
       try {
         proposedGasPrice = Number(await this.web3.eth.getGasPrice());
       } catch (err) {
-        logger.warn('Failed to get previous block gasprice.  Falling back to default');
+        // logger.warn('Failed to get previous block gasprice.  Falling back to default');
         proposedGasPrice = GAS_PRICE;
       }
     }
@@ -259,11 +259,11 @@ class Nf3 {
     const gasPrice = await this.estimateGasPrice();
     // Estimate the gasLimit
     const gas = await this.estimateGas(contractAddress, unsignedTransaction);
-    logger.debug(
-      `Transaction gasPrice was set at ${Math.ceil(
-        gasPrice / 10 ** 9,
-      )} GWei, gas limit was set at ${gas}`,
-    );
+    // logger.debug(
+    //  `Transaction gasPrice was set at ${Math.ceil(
+    //    gasPrice / 10 ** 9,
+    //  )} GWei, gas limit was set at ${gas}`,
+    // );
     const tx = {
       from: this.ethereumAddress,
       to: contractAddress,
@@ -874,7 +874,7 @@ class Nf3 {
     @async
     */
   async startProposer() {
-    const blockProposeEmitter = new EventEmitter();
+    const proposeEmitter = new EventEmitter();
     const connection = new ReconnectingWebSocket(this.optimistWsUrl, [], { WebSocket });
     this.websockets.push(connection); // save so we can close it properly later
     // we can't setup up a ping until the connection is made because the ping function
@@ -895,7 +895,7 @@ class Nf3 {
     };
     connection.onmessage = async message => {
       const msg = JSON.parse(message.data);
-      const { type, txDataToSign, block, transactions } = msg;
+      const { type, txDataToSign, block, transactions, data } = msg;
       logger.debug(`Proposer received websocket message of type ${type}`);
       if (type === 'block') {
         proposerQueue.push(async () => {
@@ -905,20 +905,21 @@ class Nf3 {
               this.stateContractAddress,
               this.BLOCK_STAKE,
             );
-            blockProposeEmitter.emit('receipt', receipt, block, transactions);
+            proposeEmitter.emit('receipt', receipt, block, transactions);
           } catch (err) {
             // block proposed is reverted. Send transactions back to mempool
-            blockProposeEmitter.emit('error', err, block, transactions);
+            proposeEmitter.emit('error', err, block, transactions);
             await axios.get(`${this.optimistBaseUrl}/block/reset-localblock`);
           }
         });
       }
+      if (type === 'rollback') proposeEmitter.emit('rollback', data);
       return null;
     };
     connection.onerror = () => logger.error('Proposer websocket connection error');
     connection.onclosed = () => logger.warn('Proposer websocket connection closed');
     // add this proposer to the list of peers that can accept direct transfers and withdraws
-    return blockProposeEmitter;
+    return proposeEmitter;
   }
 
   /**
@@ -937,67 +938,6 @@ class Nf3 {
     return res.status;
   }
 
-  /**
-    Returns an emitter, whose 'data' event fires whenever a block is
-    detected, passing out the transaction needed to propose the block. This
-    is a lower level method than `Nf3.startProposer` because it does not sign and
-    send the transaction to the blockchain. If required, `Nf3.submitTransaction`
-    can be used to do that.
-    @method
-    @async
-    @returns {Promise} A Promise that resolves into an event emitter.
-    */
-  async getNewBlockEmitter() {
-    const newBlockEmitter = new EventEmitter();
-    const connection = new ReconnectingWebSocket(this.optimistWsUrl, [], { WebSocket });
-    this.websockets.push(connection); // save so we can close it properly later
-    connection.onopen = () => {
-      // setup a ping every 15s
-      this.intervalIDs.push(
-        setInterval(() => {
-          connection._ws.ping();
-          // logger.debug('sent websocket ping');
-        }, WEBSOCKET_PING_TIME),
-      );
-      // and a listener for the pong
-      // connection._ws.on('pong', () => logger.debug('websocket received pong'));
-      logger.debug('Proposer websocket connection opened');
-      connection.send('blocks');
-    };
-    connection.onmessage = async message => {
-      const msg = JSON.parse(message.data);
-      const { type, txDataToSign } = msg;
-      if (type === 'block') {
-        newBlockEmitter.emit('data', txDataToSign);
-      }
-    };
-    return newBlockEmitter;
-  }
-
-  /**
-    Registers our address as a challenger address with the optimist container.
-    This is so that the optimist container can tell when a challenge that we have
-    committed to has appeared on chain.
-    @method
-    @async
-    @return {Promise} A promise that resolves to an axios response.
-    */
-  async registerChallenger() {
-    return axios.post(`${this.optimistBaseUrl}/challenger/add`, { address: this.ethereumAddress });
-  }
-
-  /**
-    De-registers our address as a challenger address with the optimist container.
-    @method
-    @async
-    @return {Promise} A promise that resolves to an axios response.
-    */
-  async deregisterChallenger() {
-    return axios.post(`${this.optimistBaseUrl}/challenger/remove`, {
-      address: this.ethereumAddress,
-    });
-  }
-
   /**
     Starts a Challenger that listens for challengable blocks and submits challenge
     transactions to the blockchain to challenge the block.
@@ -1013,18 +953,20 @@ class Nf3 {
       this.intervalIDs.push(
         setInterval(() => {
           connection._ws.ping();
-          // logger.debug('sent websocket ping');
+          // logger.debug('sent challenge websocket ping');
         }, WEBSOCKET_PING_TIME),
       );
       // and a listener for the pong
-      // connection._ws.on('pong', () => logger.debug('websocket received pong'));
-      logger.debug('Challenger websocket connection opened');
+      // connection._ws.on('pong', () => logger.debug('Challenge websocket received pong'));
+      logger.debug('Challenge websocket connection opened');
       connection.send('challenge');
     };
     connection.onmessage = async message => {
       const msg = JSON.parse(message.data);
-      const { type, txDataToSign } = msg;
+      const { type, txDataToSign, sender } = msg;
       logger.debug(`Challenger received websocket message of type ${type}`);
+      // if we're about to challenge, check it's actually our challenge, so as not to waste gas
+      if (type === 'challenge' && sender !== this.ethereumAddress) return null;
       if (type === 'commit' || type === 'challenge') {
         challengerQueue.push(async () => {
           try {
@@ -1038,14 +980,20 @@ class Nf3 {
             challengeEmitter.emit('error', err, type);
           }
         });
+        logger.debug(`queued ${type} ${txDataToSign}`);
       }
       return null;
     };
-    connection.onerror = () => logger.error('Challenger websocket connection error');
-    connection.onclosed = () => logger.warn('Challenger websocket connection closed');
+    connection.onerror = () => logger.error('websocket connection error');
+    connection.onclosed = () => logger.warn('websocket connection closed');
     return challengeEmitter;
   }
 
+  // method to turn challenges off and on.  Note, this does not affect the queue
+  challengeEnable(enable) {
+    return axios.post(`${this.optimistBaseUrl}/challenger/enable`, { enable });
+  }
+
   // eslint-disable-next-line class-methods-use-this
   pauseQueueChallenger() {
     return new Promise(resolve => {
@@ -1069,43 +1017,6 @@ class Nf3 {
     challengerQueue.unshift(async () => logger.info(`queue challengerQueue has been unpaused`));
   }
 
-  /**
-    Returns an emitter, whose 'data' event fires whenever a challengeable block is
-    detected, passing out the transaction needed to raise the challenge. This
-    is a lower level method than `Nf3.startChallenger` because it does not sign and
-    send the transaction to the blockchain. If required, `Nf3.submitTransaction`
-    can be used to do that.
-    @method
-    @async
-    @returns {Promise} A Promise that resolves into an event emitter.
-    */
-  async getChallengeEmitter() {
-    const newChallengeEmitter = new EventEmitter();
-    const connection = new ReconnectingWebSocket(this.optimistWsUrl, [], { WebSocket });
-    this.websockets.push(connection); // save so we can close it properly later
-    connection.onopen = () => {
-      // setup a ping every 15s
-      this.intervalIDs.push(
-        setInterval(() => {
-          connection._ws.ping();
-          // logger.debug('sent websocket ping');
-        }, WEBSOCKET_PING_TIME),
-      );
-      // and a listener for the pong
-      // connection._ws.on('pong', () => logger.debug('websocket received pong'));
-      logger.debug('Challenger websocket connection opened');
-      connection.send('challenge');
-    };
-    connection.onmessage = async message => {
-      const msg = JSON.parse(message.data);
-      const { type, txDataToSign } = msg;
-      if (type === 'challenge') {
-        newChallengeEmitter.emit('data', txDataToSign);
-      }
-    };
-    return newChallengeEmitter;
-  }
-
   /**
     Returns the balance of tokens held in layer 2
     @method
diff --git a/common-files/classes/transaction.mjs b/common-files/classes/transaction.mjs
index d67e07436..ecb8956eb 100644
--- a/common-files/classes/transaction.mjs
+++ b/common-files/classes/transaction.mjs
@@ -5,7 +5,7 @@
 An optimistic Transaction class
 */
 import gen from 'general-number';
-import Web3 from '../utils/web3.mjs';
+import Web3 from 'web3';
 import { compressProof } from '../utils/curve-maths/curves.mjs';
 import constants from '../constants/index.mjs';
 
@@ -23,7 +23,7 @@ const arrayEquality = (as, bs) => {
 
 // function to compute the keccak hash of a transaction
 function keccak(preimage) {
-  const web3 = Web3.connection();
+  const web3 = new Web3();
   const {
     value,
     fee,
diff --git a/common-files/utils/event-queue.mjs b/common-files/utils/event-queue.mjs
index d0c2f9ccd..a490ce06f 100644
--- a/common-files/utils/event-queue.mjs
+++ b/common-files/utils/event-queue.mjs
@@ -52,6 +52,15 @@ async function enqueueEvent(callback, priority, args) {
   });
 }
 
+/**
+This function immediately and unceremoniously empties the queue. It should probably
+be used with extreme care on a running queue because the exact state on emptying, and thus
+the last job that ran, will be unclear. It will cause the end event to fire.
+*/
+function emptyQueue(priority) {
+  return queues[priority].end();
+}
+
 /**
 These functions pause the queue once the current process at the head of the queue has
 completed.  It will then wait until we tell it to start again via unpause.
@@ -119,7 +128,7 @@ function waitForConfirmation(eventObject) {
 }
 
 async function dequeueEvent(priority) {
-  queues[priority].shift();
+  return queues[priority].shift();
 }
 
 async function queueManager(eventObject, eventArgs) {
@@ -169,4 +178,5 @@ export {
   waitForConfirmation,
   pauseQueue,
   unpauseQueue,
+  emptyQueue,
 };
diff --git a/config/default.js b/config/default.js
index b47ff3e59..9284b9656 100644
--- a/config/default.js
+++ b/config/default.js
@@ -75,7 +75,7 @@ module.exports = {
       // Keep keepalive interval small so that socket doesn't die
       keepaliveInterval: 1500,
     },
-    timeout: 3600000,
+    timeout: 0,
     reconnect: {
       auto: true,
       delay: 5000, // ms
@@ -136,9 +136,9 @@ module.exports = {
     ropsten: {
       name: 'Ropsten',
       chainId: 3,
-      clientApiUrl: 'https://client1.testnet.nightfall3.com',
-      optimistApiUrl: 'https://optimist1.testnet.nightfall3.com',
-      optimistWsUrl: 'wss://optimist1-ws.testnet.nightfall3.com',
+      clientApiUrl: 'https://client.testnet.nightfall3.com',
+      optimistApiUrl: 'https://optimist.testnet.nightfall3.com',
+      optimistWsUrl: 'wss://optimist-ws.testnet.nightfall3.com',
       web3WsUrl: `${process.env.ROPSTEN_NODE}`,
     },
     rinkeby: {
@@ -281,7 +281,7 @@ module.exports = {
         process.env.BOOT_CHALLENGER_ADDRESS || '0xfCb059A4dB5B961d3e48706fAC91a55Bad0035C9',
     },
     tokens: {
-      blockchain1: [
+      blockchain: [
         {
           name: 'ERC20Mock',
           address: '0x9b7bD670D87C3Dd5C808ba627c75ba7E88aD066f',
diff --git a/docker-compose.client.dev.yml b/docker-compose.client.dev.yml
index 91cf7d234..49093663b 100644
--- a/docker-compose.client.dev.yml
+++ b/docker-compose.client.dev.yml
@@ -2,7 +2,7 @@ version: '3.5'
 # Use this script for running up nightfall_3 client in 'developer' mode with local
 # bindings.  See the readme for more information.
 services:
-  client1:
+  client:
     build:
       dockerfile: client.Dockerfile
       context: .
diff --git a/docker-compose.client.yml b/docker-compose.client.yml
index 4f532cf82..ab40e6f55 100644
--- a/docker-compose.client.yml
+++ b/docker-compose.client.yml
@@ -2,14 +2,14 @@ version: '3.5'
 # Use this script for running up nightfall_3 client in 'developer' mode with local
 # bindings.  See the readme for more information.
 services:
-  client1:
+  client:
     image: ghcr.io/eyblockchain/nightfall3-client:latest
     volumes:
       - type: volume
         source: build
         target: /app/build
       - type: volume
-        source: mongodb1
+        source: mongodb
         target: /app/mongodb
     networks:
       - nightfall_network
@@ -18,13 +18,13 @@ services:
       - 8080:80
     depends_on:
       - worker
-      - rabbitmq1
+      - rabbitmq
     environment:
       MONGO_INITDB_ROOT_USERNAME: admin
       MONGO_INITDB_ROOT_PASSWORD: admin
       LOG_LEVEL: debug
       ZOKRATES_WORKER_HOST: worker
-      RABBITMQ_HOST: amqp://rabbitmq1
+      RABBITMQ_HOST: amqp://rabbitmq
       RABBITMQ_PORT: 5672
       ENABLE_QUEUE: 1
       USE_STUBS: 'false' # make sure this flag is the same as in deployer service
@@ -35,7 +35,7 @@ services:
       CONTRACT_FILES_URL: ${CONTRACT_FILES_URL}
     command: ['npm', 'run', 'dev']
 
-  rabbitmq1:
+  rabbitmq:
     image: rabbitmq
     ports:
       - '15674:15674'
@@ -58,7 +58,7 @@ services:
       CIRCUIT_FILES_URL: ${CIRCUIT_FILES_URL}
 
 volumes:
-  mongodb1:
+  mongodb:
   proving_files:
   build:
 
diff --git a/docker-compose.dev.yml b/docker-compose.dev.yml
index 7f62a2fe7..37ec15d29 100644
--- a/docker-compose.dev.yml
+++ b/docker-compose.dev.yml
@@ -20,22 +20,7 @@ services:
         source: ./config/default.js
         target: /app/admin/config/default.js
 
-  client1:
-    build:
-      dockerfile: client.Dockerfile
-      context: .
-    volumes:
-      - type: bind
-        source: ./nightfall-client/src
-        target: /app/src
-      - type: bind
-        source: ./common-files
-        target: /common-files
-      - type: bind
-        source: ./config/default.js
-        target: /app/config/default.js
-
-  client2:
+  client:
     build:
       dockerfile: client.Dockerfile
       context: .
@@ -81,7 +66,7 @@ services:
         source: ./nightfall-deployer/entrypoint.sh
         target: /app/entrypoint.sh
 
-  optimist1:
+  optimist:
     build:
       dockerfile: optimist.Dockerfile
       context: .
@@ -97,21 +82,6 @@ services:
         source: ./config/default.js
         target: /app/config/default.js
 
-  optimist2:
-    build:
-      dockerfile: optimist.Dockerfile
-      context: .
-    volumes:
-      - type: bind
-        source: ./nightfall-optimist/src
-        target: /app/src
-      - type: bind
-        source: ./common-files
-        target: /common-files
-      - type: bind
-        source: ./config/default.js
-        target: /app/config/default.js
-
   worker:
     #  image: 3800decac71d
     build:
@@ -134,4 +104,3 @@ services:
       # to use with postman and etc
       - 8091:80
     entrypoint: [ "npm", "run", "start" ]
-  
\ No newline at end of file
diff --git a/docker-compose.ganache.yml b/docker-compose.ganache.yml
index f81df399b..6968e5540 100644
--- a/docker-compose.ganache.yml
+++ b/docker-compose.ganache.yml
@@ -3,7 +3,7 @@ version: '3.5'
 # bindings and using a Ganache private blockchain.  See the readme for more information.
 # It acts as an override file for docker-compose.yml
 services:
-  blockchain1:
+  blockchain:
     image: trufflesuite/ganache-cli:v6.12.1
     ports:
       - 8546:8546
diff --git a/docker-compose.host.docker.internal.yml b/docker-compose.host.docker.internal.yml
index ca1a0e554..4aa856f5a 100644
--- a/docker-compose.host.docker.internal.yml
+++ b/docker-compose.host.docker.internal.yml
@@ -10,15 +10,8 @@ services:
     environment:
       BLOCKCHAIN_WS_HOST: host.docker.internal
       ETH_NETWORK: development
-      
-  client1:
-    extra_hosts:
-      - 'host.docker.internal:host-gateway'
-    environment:
-      BLOCKCHAIN_WS_HOST: host.docker.internal
-      AUTOSTART_RETRIES: 100
 
-  client2:
+  client:
     extra_hosts:
       - 'host.docker.internal:host-gateway'
     environment:
@@ -35,14 +28,7 @@ services:
       ETH_NETWORK: development
       BLOCKCHAIN_WS_HOST: host.docker.internal
 
-  optimist1:
-    extra_hosts:
-      - 'host.docker.internal:host-gateway'
-    environment:
-      BLOCKCHAIN_WS_HOST: host.docker.internal
-      AUTOSTART_RETRIES: 100
-
-  optimist2:
+  optimist:
     extra_hosts:
       - 'host.docker.internal:host-gateway'
     environment:
diff --git a/docker-compose.images.example.yml b/docker-compose.images.example.yml
index 9904e1c28..8a2175594 100644
--- a/docker-compose.images.example.yml
+++ b/docker-compose.images.example.yml
@@ -2,14 +2,14 @@ version: '3.5'
 # Use this script for running up nightfall_3 with images
 # If you replace the main docker-compose with this file, it should work!
 services:
-  client1:
+  client:
     image: ghcr.io/eyblockchain/nightfall3-client:latest
     volumes:
       - type: volume
         source: build
         target: /app/build
       - type: volume
-        source: mongodb1
+        source: mongodb
         target: /app/mongodb
     networks:
       - nightfall_network
@@ -19,48 +19,18 @@ services:
     depends_on:
       - deployer
       - worker
-      - rabbitmq1
+      - rabbitmq
     environment:
       MONGO_INITDB_ROOT_USERNAME: admin
       MONGO_INITDB_ROOT_PASSWORD: admin
       LOG_LEVEL: debug
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       ZOKRATES_WORKER_HOST: worker
-      RABBITMQ_HOST: amqp://rabbitmq1
+      RABBITMQ_HOST: amqp://rabbitmq
       RABBITMQ_PORT: 5672
       ENABLE_QUEUE: 1
-      OPTIMIST_HOST: optimist1
-      OPTIMIST_PORT: 80
-      USE_STUBS: 'false' # make sure this flag is the same as in deployer service
-    command: ['npm', 'run', 'dev']
-
-  client2:
-    image: ghcr.io/eyblockchain/nightfall3-client:latest
-    volumes:
-      - type: volume
-        source: build
-        target: /app/build
-    networks:
-      - nightfall_network
-    ports:
-      - 27018:27017
-      - 8084:80
-    depends_on:
-      - deployer
-      - worker
-      - rabbitmq2
-    environment:
-      MONGO_INITDB_ROOT_USERNAME: admin
-      MONGO_INITDB_ROOT_PASSWORD: admin
-      LOG_LEVEL: error
-      BLOCKCHAIN_WS_HOST: blockchain1
-      BLOCKCHAIN_PORT: 8546
-      ZOKRATES_WORKER_HOST: worker
-      RABBITMQ_HOST: amqp://rabbitmq2
-      RABBITMQ_PORT: 5672
-      ENABLE_QUEUE: 1
-      OPTIMIST_HOST: optimist2
+      OPTIMIST_HOST: optimist
       OPTIMIST_PORT: 80
       USE_STUBS: 'false' # make sure this flag is the same as in deployer service
     command: ['npm', 'run', 'dev']
@@ -81,13 +51,13 @@ services:
       LOG_LEVEL: debug
       # ETH_NETWORK sets the network selected by Truffle from truffle-config.js
       # startup routines will wait for a blockchain client to be reachable on this network
-      ETH_NETWORK: blockchain1
-      BLOCKCHAIN_WS_HOST: blockchain1
+      ETH_NETWORK: blockchain
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       ZOKRATES_WORKER_HOST: worker
       USE_STUBS: 'false'
 
-  optimist1:
+  optimist:
     image: ghcr.io/eyblockchain/nightfall3-optimist:latest
     depends_on:
       - deployer
@@ -103,7 +73,7 @@ services:
         target: /app/build/
     environment:
       WEBSOCKET_PORT: 8080
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       HASH_TYPE: poseidon
       LOG_LEVEL: debug
@@ -111,32 +81,7 @@ services:
       TRANSACTIONS_PER_BLOCK: ${TRANSACTIONS_PER_BLOCK:-2}
     command: ['npm', 'run', 'dev']
 
-  optimist2:
-    image: ghcr.io/eyblockchain/nightfall3-optimist:latest
-    depends_on:
-      - deployer
-    networks:
-      - nightfall_network
-    ports:
-      - 8085:80
-      # websocket port for Optimist is on localhost:8086
-      - 8086:8080
-    volumes:
-      - type: volume
-        source: build
-        target: /app/build/
-      # - type: bind
-    environment:
-      WEBSOCKET_PORT: 8080
-      BLOCKCHAIN_WS_HOST: blockchain1
-      BLOCKCHAIN_PORT: 8546
-      HASH_TYPE: poseidon
-      LOG_LEVEL: error
-      IS_CHALLENGER: 'true'
-      TRANSACTIONS_PER_BLOCK: ${TRANSACTIONS_PER_BLOCK:-2}
-    command: ['npm', 'run', 'dev']
-
-  rabbitmq1:
+  rabbitmq:
     image: rabbitmq
     ports:
       - '15674:15674'
@@ -144,14 +89,6 @@ services:
     networks:
       - nightfall_network
 
-  rabbitmq2:
-    image: rabbitmq
-    ports:
-      - '15675:15674'
-      - '5673:5672'
-    networks:
-      - nightfall_network
-
   worker:
     image: ghcr.io/eyblockchain/nightfall3-worker
     volumes:
@@ -166,8 +103,7 @@ services:
       LOG_LEVEL: info
 
 volumes:
-  mongodb1:
-  mongodb2:
+  mongodb:
   proving_files:
   build:
 
diff --git a/docker-compose.ropsten.yml b/docker-compose.ropsten.yml
index 73c6473a8..5bcac99ad 100644
--- a/docker-compose.ropsten.yml
+++ b/docker-compose.ropsten.yml
@@ -1,12 +1,6 @@
 version: '3.5'
 services:
-  client1:
-    environment:
-      BLOCKCHAIN_URL: $ROPSTEN_NODE
-      USE_EXTERNAL_NODE: 'true'
-      AUTOSTART_RETRIES: 600
-
-  client2:
+  client:
     environment:
       BLOCKCHAIN_URL: $ROPSTEN_NODE
       USE_EXTERNAL_NODE: 'true'
@@ -22,13 +16,7 @@ services:
       FROM_ADDRESS: ${FROM_ADDRESS:-0x29100E7E3dA6654BF63d9E7804ADe518aCc5AaA5}
       ETH_PRIVATE_KEY: $ETH_PRIVATE_KEY
 
-  optimist1:
-    environment:
-      BLOCKCHAIN_URL: $ROPSTEN_NODE
-      USE_EXTERNAL_NODE: 'true'
-      AUTOSTART_RETRIES: 600
-
-  optimist2:
+  optimist:
     environment:
       BLOCKCHAIN_URL: $ROPSTEN_NODE
       USE_EXTERNAL_NODE: 'true'
diff --git a/docker-compose.standalone.geth.yml b/docker-compose.standalone.geth.yml
index 732d1ba0d..d75f2f77f 100644
--- a/docker-compose.standalone.geth.yml
+++ b/docker-compose.standalone.geth.yml
@@ -14,7 +14,7 @@ services:
         ipv4_address: 172.16.239.10
     command: bootnode --nodekey=setup/node.key
 
-  blockchain1:
+  blockchain:
     image: ethereum/client-go:stable
     ports:
       - 8546:8546
diff --git a/docker-compose.stubs.yml b/docker-compose.stubs.yml
index 013523eaf..1665955c6 100644
--- a/docker-compose.stubs.yml
+++ b/docker-compose.stubs.yml
@@ -1,11 +1,7 @@
 version: '3.5'
 # Use this script for making nightfall_3 use stubs.
 services:
-    client1:
-      environment:
-        USE_STUBS: 'true' # make sure this flag is the same as in deployer service
-
-    client2:
+    client:
       environment:
         USE_STUBS: 'true' # make sure this flag is the same as in deployer service
 
diff --git a/docker-compose.yml b/docker-compose.yml
index 96f8a3e12..22ba48973 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -11,19 +11,19 @@ services:
         source: build
         target: /app/build/
     environment:
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       LOG_LEVEL: error
-      ETH_NETWORK: blockchain1
+      ETH_NETWORK: blockchain
 
-  client1:
+  client:
     image: ghcr.io/eyblockchain/nightfall3-client:latest
     volumes:
       - type: volume
         source: build
         target: /app/build
       - type: volume
-        source: mongodb1
+        source: mongodb
         target: /app/mongodb
     networks:
       - nightfall_network
@@ -33,51 +33,18 @@ services:
     depends_on:
       - deployer
       - worker
-      - rabbitmq1
+      - rabbitmq
     environment:
       MONGO_INITDB_ROOT_USERNAME: admin
       MONGO_INITDB_ROOT_PASSWORD: admin
       LOG_LEVEL: debug
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       ZOKRATES_WORKER_HOST: worker
-      RABBITMQ_HOST: amqp://rabbitmq1
+      RABBITMQ_HOST: amqp://rabbitmq
       RABBITMQ_PORT: 5672
       ENABLE_QUEUE: 1
-      OPTIMIST_HOST: optimist1
-      OPTIMIST_PORT: 80
-      USE_STUBS: 'false' # make sure this flag is the same as in deployer service
-    command: ['npm', 'run', 'dev']
-
-  client2:
-    image: ghcr.io/eyblockchain/nightfall3-client:latest
-    volumes:
-      - type: volume
-        source: build
-        target: /app/build
-      - type: volume
-        source: mongodb2
-        target: /app/mongodb
-    networks:
-      - nightfall_network
-    ports:
-      - 27018:27017
-      - 8084:80
-    depends_on:
-      - deployer
-      - worker
-      - rabbitmq2
-    environment:
-      MONGO_INITDB_ROOT_USERNAME: admin
-      MONGO_INITDB_ROOT_PASSWORD: admin
-      LOG_LEVEL: error
-      BLOCKCHAIN_WS_HOST: blockchain1
-      BLOCKCHAIN_PORT: 8546
-      ZOKRATES_WORKER_HOST: worker
-      RABBITMQ_HOST: amqp://rabbitmq2
-      RABBITMQ_PORT: 5672
-      ENABLE_QUEUE: 1
-      OPTIMIST_HOST: optimist2
+      OPTIMIST_HOST: optimist
       OPTIMIST_PORT: 80
       USE_STUBS: 'false' # make sure this flag is the same as in deployer service
     command: ['npm', 'run', 'dev']
@@ -96,8 +63,8 @@ services:
       LOG_LEVEL: debug
       # ETH_NETWORK sets the network selected by Truffle from truffle-config.js
       # startup routines will wait for a blockchain client to be reachable on this network
-      ETH_NETWORK: blockchain1
-      BLOCKCHAIN_WS_HOST: blockchain1
+      ETH_NETWORK: blockchain
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       ZOKRATES_WORKER_HOST: worker
       USE_STUBS: 'false'
@@ -114,10 +81,10 @@ services:
         source: proving_files
         target: /app/public/
 
-  optimist1:
+  optimist:
     image: ghcr.io/eyblockchain/nightfall3-optimist:latest
-    depends_on:
-      - deployer
+  #  depends_on:
+  #    - deployer
     networks:
       - nightfall_network
     ports:
@@ -130,7 +97,7 @@ services:
         target: /app/build/
     environment:
       WEBSOCKET_PORT: 8080
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       HASH_TYPE: poseidon
       LOG_LEVEL: debug
@@ -138,31 +105,7 @@ services:
       TRANSACTIONS_PER_BLOCK: ${TRANSACTIONS_PER_BLOCK:-2}
     command: ['npm', 'run', 'dev']
 
-  optimist2:
-    image: ghcr.io/eyblockchain/nightfall3-optimist:latest
-    depends_on:
-      - deployer
-    networks:
-      - nightfall_network
-    ports:
-      - 8085:80
-      # websocket port for Optimist is on localhost:8086
-      - 8086:8080
-    volumes:
-      - type: volume
-        source: build
-        target: /app/build/
-    environment:
-      WEBSOCKET_PORT: 8080
-      BLOCKCHAIN_WS_HOST: blockchain1
-      BLOCKCHAIN_PORT: 8546
-      HASH_TYPE: poseidon
-      LOG_LEVEL: error
-      IS_CHALLENGER: 'false'
-      TRANSACTIONS_PER_BLOCK: ${TRANSACTIONS_PER_BLOCK:-2}
-    command: ['npm', 'run', 'dev']
-
-  rabbitmq1:
+  rabbitmq:
     image: rabbitmq
     ports:
       - '15674:15674'
@@ -170,14 +113,6 @@ services:
     networks:
       - nightfall_network
 
-  rabbitmq2:
-    image: rabbitmq
-    ports:
-      - '15675:15674'
-      - '5673:5672'
-    networks:
-      - nightfall_network
-
   worker:
     #  image: 3800decac71d
     image: ghcr.io/eyblockchain/nightfall3-worker:latest
@@ -195,8 +130,7 @@ services:
       MPC: ${MPC}
 
 volumes:
-  mongodb1: null
-  mongodb2: null
+  mongodb: null
   proving_files: null
   build: null
 networks:
diff --git a/nightfall-client/dropAll.sh b/nightfall-client/dropAll.sh
index a83234b79..5dfc109dc 100755
--- a/nightfall-client/dropAll.sh
+++ b/nightfall-client/dropAll.sh
@@ -1,6 +1,6 @@
 #! /bin/bash
 
-docker exec -t nightfall_3_optimist1_1 bash -c \
+docker exec -t nightfall_3_optimist_1 bash -c \
     'mongo --quiet --eval "db = db.getSiblingDB(\"optimist_data\");
     db.blocks.drop( { writeConcern: { w: \"majority\" } } );
     db.nullifiers.drop( { writeConcern: { w: \"majority\" } } );
diff --git a/nightfall-client/start-client b/nightfall-client/start-client
index d35920d7a..9945d19a9 100755
--- a/nightfall-client/start-client
+++ b/nightfall-client/start-client
@@ -37,9 +37,9 @@ fi
 
 if [ -n "$REMOVE_VOLUMES" ]; then
   # if-else block checks - volume exist and then removes it.
-  if [[ $(echo $VOLUME_LIST | grep nightfall_3_mongodb1) ]]; then
+  if [[ $(echo $VOLUME_LIST | grep nightfall_3_mongodb) ]]; then
     echo -n 'Removing '
-    docker volume rm nightfall_3_mongodb1
+    docker volume rm nightfall_3_mongodb
   fi
 
   if [[ $(echo $VOLUME_LIST | grep nightfall_3_build) ]]; then
diff --git a/nightfall-deployer/truffle-config.js b/nightfall-deployer/truffle-config.js
index 7bf292c35..e8f3c5951 100644
--- a/nightfall-deployer/truffle-config.js
+++ b/nightfall-deployer/truffle-config.js
@@ -45,10 +45,10 @@ module.exports = {
     // options below to some value.
     //
 
-    blockchain1: {
+    blockchain: {
       // host: 'blockchain', // Localhost (default: none)
       // port: 8546, // Standard Ethereum port (default: none)
-      url: 'ws://blockchain1:8546',
+      url: 'ws://blockchain:8546',
       network_id: 1337, // Any network (default: none)
       gas: 1000000000,
       websockets: true,
diff --git a/nightfall-optimist/package-lock.json b/nightfall-optimist/package-lock.json
index 8068401f8..e8d863890 100644
--- a/nightfall-optimist/package-lock.json
+++ b/nightfall-optimist/package-lock.json
@@ -1460,6 +1460,7 @@
         },
         "big-integer": {
           "version": "1.6.51",
+          "resolved": false,
           "integrity": "sha512-GPEid2Y9QU1Exl1rpO9B2IPJGHPSupF5GnVIP0blYvNOMer2bTvSWs1jGOUg04hTmu67nmLsQ9TBo1puaotBHg=="
         },
         "bignumber.js": {
@@ -4022,7 +4023,7 @@
             "buffer": "^5.0.5",
             "eth-lib": "^0.1.26",
             "fs-extra": "^4.0.2",
-            "got": "11.8.5",
+            "got": "^7.1.0",
             "mime-types": "^2.1.16",
             "mkdirp-promise": "^5.0.1",
             "mock-fs": "^4.1.0",
@@ -5049,11 +5050,6 @@
       "resolved": "https://registry.npmjs.org/dom-walk/-/dom-walk-0.1.2.tgz",
       "integrity": "sha512-6QvTW9mrGeIegrFXdtQi9pk7O/nSK6lSdXW2eqUspN5LWD7UTji2Fqw5V2YLjBpHEoU9Xl/eUWNpDeZvoyOv2w=="
     },
-    "duplexer3": {
-      "version": "0.1.5",
-      "resolved": "https://registry.npmjs.org/duplexer3/-/duplexer3-0.1.5.tgz",
-      "integrity": "sha512-1A8za6ws41LQgv9HrE/66jyC5yuSjQ3L/KOpFtoBilsAK2iA2wuS5rTt1OCzIvtS2V7nVmedsUU+DGRcjBmOYA=="
-    },
     "ecc-jsbn": {
       "version": "0.1.2",
       "resolved": "https://registry.npmjs.org/ecc-jsbn/-/ecc-jsbn-0.1.2.tgz",
@@ -5833,24 +5829,11 @@
         "get-intrinsic": "^1.1.1"
       }
     },
-    "has-symbol-support-x": {
-      "version": "1.4.2",
-      "resolved": "https://registry.npmjs.org/has-symbol-support-x/-/has-symbol-support-x-1.4.2.tgz",
-      "integrity": "sha512-3ToOva++HaW+eCpgqZrCfN51IPB+7bJNVT6CUATzueB5Heb8o6Nam0V3HG5dlDvZU1Gn5QLcbahiKw/XVk5JJw=="
-    },
     "has-symbols": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/has-symbols/-/has-symbols-1.0.3.tgz",
       "integrity": "sha512-l3LCuF6MgDNwTDKkdYGEihYjt5pRPbEg46rtlmnSPlUbgmB8LOIrKJbYYFBSbnPaJexMKtiPO8hmeRjRz2Td+A=="
     },
-    "has-to-string-tag-x": {
-      "version": "1.4.1",
-      "resolved": "https://registry.npmjs.org/has-to-string-tag-x/-/has-to-string-tag-x-1.4.1.tgz",
-      "integrity": "sha512-vdbKfmw+3LoOYVr+mtxHaX5a96+0f3DljYd8JOqvOLsf5mw2Otda2qCDT9qRqLAhrjyQ0h7ual5nOiASpsGNFw==",
-      "requires": {
-        "has-symbol-support-x": "^1.4.1"
-      }
-    },
     "has-tostringtag": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/has-tostringtag/-/has-tostringtag-1.0.0.tgz",
@@ -6130,16 +6113,6 @@
         "has-tostringtag": "^1.0.0"
       }
     },
-    "is-object": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/is-object/-/is-object-1.0.2.tgz",
-      "integrity": "sha512-2rRIahhZr2UWb45fIOuvZGpFtz0TyOZLf32KxBbSoUCeZR495zCKlWUKKUByk3geS2eAs7ZAABt0Y/Rx0GiQGA=="
-    },
-    "is-plain-obj": {
-      "version": "1.1.0",
-      "resolved": "https://registry.npmjs.org/is-plain-obj/-/is-plain-obj-1.1.0.tgz",
-      "integrity": "sha512-yvkRyxmFKEOQ4pNXCmJG5AEQNlXJS5LaONXo5/cLdTZdWvsZ1ioJEonLGAosKlMWE8lwUy/bJzMjcw8az73+Fg=="
-    },
     "is-regex": {
       "version": "1.1.4",
       "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.1.4.tgz",
@@ -6149,11 +6122,6 @@
         "has-tostringtag": "^1.0.0"
       }
     },
-    "is-retry-allowed": {
-      "version": "1.2.0",
-      "resolved": "https://registry.npmjs.org/is-retry-allowed/-/is-retry-allowed-1.2.0.tgz",
-      "integrity": "sha512-RUbUeKwvm3XG2VYamhJL1xFktgjvPzL0Hq8C+6yrWIswDy3BIXGqCxhxkc30N9jqK311gVU137K8Ei55/zVJRg=="
-    },
     "is-shared-array-buffer": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/is-shared-array-buffer/-/is-shared-array-buffer-1.0.2.tgz",
@@ -6224,15 +6192,6 @@
       "resolved": "https://registry.npmjs.org/isstream/-/isstream-0.1.2.tgz",
       "integrity": "sha512-Yljz7ffyPbrLpLngrMtZ7NduUgVvi6wG9RJ9IUcyCd59YQ911PBJphODUcbOVbqYfxe1wuYf/LJ8PauMRwsM/g=="
     },
-    "isurl": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/isurl/-/isurl-1.0.0.tgz",
-      "integrity": "sha512-1P/yWsxPlDtn7QeRD+ULKQPaIaN6yF368GZ2vDfv0AL0NwpStafjWCDDdn0k8wgFMWpVAqG7oJhxHnlud42i9w==",
-      "requires": {
-        "has-to-string-tag-x": "^1.2.0",
-        "is-object": "^1.0.1"
-      }
-    },
     "joycon": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/joycon/-/joycon-3.1.1.tgz",
@@ -6889,11 +6848,6 @@
       "resolved": "https://registry.npmjs.org/p-cancelable/-/p-cancelable-3.0.0.tgz",
       "integrity": "sha512-mlVgR3PGuzlo0MmTdk4cXqXWlwQDLnONTAg6sm62XkMJEiRxN3GL3SffkYvqwonbkJBcrI7Uvv5Zh9yjvn2iUw=="
     },
-    "p-finally": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/p-finally/-/p-finally-1.0.0.tgz",
-      "integrity": "sha512-LICb2p9CB7FS+0eR1oqWnHhp0FljGLZCWBE9aix0Uye9W8LTQPwMTYVGWQWIw9RdQiDg4+epXQODwIYJtSJaow=="
-    },
     "p-limit": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/p-limit/-/p-limit-3.1.0.tgz",
@@ -6912,14 +6866,6 @@
         "p-limit": "^3.0.2"
       }
     },
-    "p-timeout": {
-      "version": "1.2.1",
-      "resolved": "https://registry.npmjs.org/p-timeout/-/p-timeout-1.2.1.tgz",
-      "integrity": "sha512-gb0ryzr+K2qFqFv6qi3khoeqMZF/+ajxQipEF6NteZVnvz9tzdsfAVj3lYtn1gAXvH5lfLwfxEII799gt/mRIA==",
-      "requires": {
-        "p-finally": "^1.0.0"
-      }
-    },
     "parse-asn1": {
       "version": "5.1.6",
       "resolved": "https://registry.npmjs.org/parse-asn1/-/parse-asn1-5.1.6.tgz",
@@ -7060,11 +7006,6 @@
       "resolved": "https://registry.npmjs.org/pino-std-serializers/-/pino-std-serializers-6.0.0.tgz",
       "integrity": "sha512-mMMOwSKrmyl+Y12Ri2xhH1lbzQxwwpuru9VjyJpgFIH4asSj88F2csdMwN6+M5g1Ll4rmsYghHLQJw81tgZ7LQ=="
     },
-    "prepend-http": {
-      "version": "1.0.4",
-      "resolved": "https://registry.npmjs.org/prepend-http/-/prepend-http-1.0.4.tgz",
-      "integrity": "sha512-PhmXi5XmoyKw1Un4E+opM2KcsJInDvKyuOumcjjw3waw86ZNjHwVUOOWLc4bCzLdcKNaWBH9e99sbWzDQsVaYg=="
-    },
     "process": {
       "version": "0.11.10",
       "resolved": "https://registry.npmjs.org/process/-/process-0.11.10.tgz",
@@ -7681,7 +7622,7 @@
         "buffer": "^5.0.5",
         "eth-lib": "^0.1.26",
         "fs-extra": "^4.0.2",
-        "got": "11.8.5",
+        "got": "^7.1.0",
         "mime-types": "^2.1.16",
         "mkdirp-promise": "^5.0.1",
         "mock-fs": "^4.1.0",
@@ -7960,24 +7901,11 @@
         "punycode": "^2.1.0"
       }
     },
-    "url-parse-lax": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/url-parse-lax/-/url-parse-lax-1.0.0.tgz",
-      "integrity": "sha512-BVA4lR5PIviy2PMseNd2jbFQ+jwSwQGdJejf5ctd1rEXt0Ypd7yanUK9+lYechVlN5VaTJGsu2U/3MDDu6KgBA==",
-      "requires": {
-        "prepend-http": "^1.0.1"
-      }
-    },
     "url-set-query": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/url-set-query/-/url-set-query-1.0.0.tgz",
       "integrity": "sha512-3AChu4NiXquPfeckE5R5cGdiHCMWJx1dwCWOmWIL4KHAziJNOFIYJlpGFeKDvwLPHovZRCxK3cYlwzqI9Vp+Gg=="
     },
-    "url-to-options": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/url-to-options/-/url-to-options-1.0.1.tgz",
-      "integrity": "sha512-0kQLIzG4fdk/G5NONku64rSH/x32NOA39LVQqlK8Le6lvTF6GGRJpqaQFGgU+CLwySIqBSMdwYM0sYcW9f6P4A=="
-    },
     "utf-8-validate": {
       "version": "5.0.9",
       "resolved": "https://registry.npmjs.org/utf-8-validate/-/utf-8-validate-5.0.9.tgz",
diff --git a/nightfall-optimist/src/classes/block.mjs b/nightfall-optimist/src/classes/block.mjs
index 35f1467e0..303389f9a 100644
--- a/nightfall-optimist/src/classes/block.mjs
+++ b/nightfall-optimist/src/classes/block.mjs
@@ -3,12 +3,12 @@ An optimistic layer 2 Block class
 */
 import config from 'config';
 import Timber from 'common-files/classes/timber.mjs';
-import Web3 from 'common-files/utils/web3.mjs';
 import constants from 'common-files/constants/index.mjs';
 import { getLatestBlockInfo, getTreeByBlockNumberL2 } from '../services/database.mjs';
+import { buildBlockSolidityStruct, calcBlockHash } from '../services/block-utils.mjs';
 
 const { TIMBER_HEIGHT, TXHASH_TREE_HEIGHT, HASH_TYPE, TXHASH_TREE_HASH_TYPE } = config;
-const { ZERO, BLOCK_TYPES } = constants;
+const { ZERO } = constants;
 
 /**
 This Block class does not have the Block components that are computed on-chain.
@@ -173,34 +173,13 @@ class Block {
   }
 
   static calcHash(block) {
-    const web3 = Web3.connection();
-    const { proposer, root, leafCount, blockNumberL2, previousBlockHash, transactionHashesRoot } =
-      block;
-    const blockArray = [
-      leafCount,
-      proposer,
-      root,
-      blockNumberL2,
-      previousBlockHash,
-      transactionHashesRoot,
-    ];
-    const encoded = web3.eth.abi.encodeParameters([BLOCK_TYPES], [blockArray]);
-    return web3.utils.soliditySha3({ t: 'bytes', v: encoded });
+    return calcBlockHash(block);
   }
 
   // remove properties that do not get sent to the blockchain returning
   // a new object (don't mutate the original)
   static buildSolidityStruct(block) {
-    const { proposer, root, leafCount, blockNumberL2, previousBlockHash, transactionHashesRoot } =
-      block;
-    return {
-      leafCount: Number(leafCount),
-      proposer,
-      root,
-      blockNumberL2: Number(blockNumberL2),
-      previousBlockHash,
-      transactionHashesRoot,
-    };
+    return buildBlockSolidityStruct(block);
   }
 }
 
diff --git a/nightfall-optimist/src/event-handlers/block-proposed.mjs b/nightfall-optimist/src/event-handlers/block-proposed.mjs
index e8c9f1ef9..f846f42e0 100644
--- a/nightfall-optimist/src/event-handlers/block-proposed.mjs
+++ b/nightfall-optimist/src/event-handlers/block-proposed.mjs
@@ -7,7 +7,7 @@ import { enqueueEvent } from 'common-files/utils/event-queue.mjs';
 import constants from 'common-files/constants/index.mjs';
 import { checkBlock } from '../services/check-block.mjs';
 import BlockError from '../classes/block-error.mjs';
-import { createChallenge } from '../services/challenges.mjs';
+import { createChallenge, commitToChallenge } from '../services/challenges.mjs';
 import {
   removeTransactionsFromMemPool,
   removeCommitmentsFromMemPool,
@@ -129,8 +129,14 @@ async function blockProposedEventHandler(data) {
         transactionHashL1,
         ...block,
       });
-      await enqueueEvent(() => logger.info('Stop Until Rollback'), 2);
-      await createChallenge(block, transactions, err);
+      const txDataToSign = await createChallenge(block, transactions, err);
+      // push the challenge into the stop queue.  This will stop blocks being
+      // made until the challenge has run and a rollback has happened.  We could
+      // push anything into the queue and that would work but it's useful to
+      // have the actual challenge to support syncing
+      logger.debug('enqueuing event to stop queue');
+      await enqueueEvent(commitToChallenge, 2, txDataToSign);
+      await commitToChallenge(txDataToSign);
     } else {
       logger.error(err.stack);
       throw new Error(err);
diff --git a/nightfall-optimist/src/event-handlers/challenge-commit.mjs b/nightfall-optimist/src/event-handlers/challenge-commit.mjs
index 6d733accf..a8bef5a1d 100644
--- a/nightfall-optimist/src/event-handlers/challenge-commit.mjs
+++ b/nightfall-optimist/src/event-handlers/challenge-commit.mjs
@@ -1,22 +1,24 @@
 import logger from 'common-files/utils/logger.mjs';
 import { revealChallenge } from '../services/challenges.mjs';
-import { getCommit, isChallengerAddressMine } from '../services/database.mjs';
+import { getCommit } from '../services/database.mjs';
 
 async function committedToChallengeEventHandler(data) {
   const { commitHash, sender } = data.returnValues;
   logger.debug(
     `Received commmitted to challenge event, with hash ${commitHash} and sender ${sender}`,
   );
-  const challengerIsMe = await isChallengerAddressMine(sender);
-  if (!challengerIsMe) return; // it's not us - nothing to do
-  logger.info(`Our challenge commitment has been mined, sending reveal`);
+  logger.info('A challenge commitment has been mined');
   const { txDataToSign, retrieved } = await getCommit(commitHash);
-  if (txDataToSign === null) throw new Error('Commit hash not found in database');
+  // We may not find the commitment. In this case, it's probably not ours so we take no action
+  if (txDataToSign === null) {
+    logger.debug('Commit hash not found in database');
+    return;
+  }
   // if retrieved is true, then we've looked up this commit before and we assume
   // we have already revealed it - thus we don't reveal it again because that would
   // just waste gas.  This could happen if a chain reorg were to re-emit the
   // CommittedToChallenge event.
-  if (!retrieved) revealChallenge(txDataToSign);
+  if (!retrieved) revealChallenge(txDataToSign, sender);
 }
 
 export default committedToChallengeEventHandler;
diff --git a/nightfall-optimist/src/event-handlers/rollback.mjs b/nightfall-optimist/src/event-handlers/rollback.mjs
index 5b01a6852..82c420914 100644
--- a/nightfall-optimist/src/event-handlers/rollback.mjs
+++ b/nightfall-optimist/src/event-handlers/rollback.mjs
@@ -20,6 +20,7 @@ import {
 } from '../services/check-block.mjs';
 import Block from '../classes/block.mjs';
 import checkTransaction from '../services/transaction-checker.mjs';
+import { signalRollbackCompleted } from '../services/block-assembler.mjs';
 
 async function rollbackEventHandler(data) {
   const { blockNumberL2 } = data.returnValues;
@@ -82,7 +83,7 @@ async function rollbackEventHandler(data) {
   await dequeueEvent(2); // Remove an event from the stopQueue.
   // A Rollback triggers a NewCurrentProposer event which shoudl trigger queue[0].end()
   // But to be safe we enqueue a helper event to guarantee queue[0].end() runs.
-  await enqueueEvent(() => logger.info(`Rollback Completed`), 0);
+  await enqueueEvent(() => signalRollbackCompleted(), 0);
 }
 
 export default rollbackEventHandler;
diff --git a/nightfall-optimist/src/index.mjs b/nightfall-optimist/src/index.mjs
index 84d9fabfc..b5414f780 100644
--- a/nightfall-optimist/src/index.mjs
+++ b/nightfall-optimist/src/index.mjs
@@ -35,8 +35,9 @@ const main = async () => {
     queues[0].on('end', () => {
       // We do the proposer isMe check here to fail fast instead of re-enqueing.
       // We check if the queue[2] is empty, this is safe it is manually enqueued/dequeued.
+      // logger.debug(`proposer is, ${proposer.address}, stop queue length is ${queues[2].length}`);
       if (proposer.isMe && queues[2].length === 0) {
-        // logger.info('Queue has emptied. Queueing block assembler.');
+        // logger.debug('Queue has emptied. Queueing block assembler.');
         return enqueueEvent(conditionalMakeBlock, 0, proposer);
       }
       // eslint-disable-next-line no-void, no-useless-return
diff --git a/nightfall-optimist/src/routes/challenger.mjs b/nightfall-optimist/src/routes/challenger.mjs
index 73e73935c..802161757 100644
--- a/nightfall-optimist/src/routes/challenger.mjs
+++ b/nightfall-optimist/src/routes/challenger.mjs
@@ -3,29 +3,21 @@ Routes for setting and removing valid challenger addresses.
 */
 import express from 'express';
 import logger from 'common-files/utils/logger.mjs';
-import { addChallengerAddress, removeChallengerAddress } from '../services/database.mjs';
+import { emptyQueue } from 'common-files/utils/event-queue.mjs';
+import { startMakingChallenges, stopMakingChallenges } from '../services/challenges.mjs';
 
 const router = express.Router();
 
-router.post('/add', async (req, res, next) => {
-  logger.debug('add endpoint received POST');
+router.post('/enable', async (req, res, next) => {
+  logger.debug('challenge endpoint received POST');
   try {
-    const { address } = req.body;
-    const result = await addChallengerAddress(address);
+    const { enable } = req.body;
+    const result =
+      enable === true ? (emptyQueue(2), startMakingChallenges()) : stopMakingChallenges();
     res.json(result);
   } catch (err) {
     next(err);
   }
 });
 
-router.post('/remove', async (req, res, next) => {
-  logger.debug('remove endpoint received post');
-  try {
-    const { address } = req.body;
-    res.json(await removeChallengerAddress(address));
-  } catch (err) {
-    next(err);
-  }
-});
-
 export default router;
diff --git a/nightfall-optimist/src/services/block-assembler.mjs b/nightfall-optimist/src/services/block-assembler.mjs
index d89eb06a7..f0d73103e 100644
--- a/nightfall-optimist/src/services/block-assembler.mjs
+++ b/nightfall-optimist/src/services/block-assembler.mjs
@@ -36,6 +36,27 @@ export function setMakeNow(_makeNow = true) {
   makeNow = _makeNow;
 }
 
+/**
+Function to indicate to a listening proposer that a rollback has been completed. This
+is of little use at the moment but will enable the proposer to take actions such as
+checking they haven't been removed. This function may be a little out of place here but
+we need to use the proposer's websocket!
+*/
+export async function signalRollbackCompleted(data) {
+  // check that the websocket exists (it should) and its readyState is OPEN
+  // before sending. If not wait until the challenger reconnects
+  let tryCount = 0;
+  while (!ws || ws.readyState !== WebSocket.OPEN) {
+    await new Promise(resolve => setTimeout(resolve, 3000)); // eslint-disable-line no-await-in-loop
+    logger.warn(
+      `Websocket to proposer is closed for rollback complete.  Waiting for challenger to reconnect`,
+    );
+    if (tryCount++ > 100) throw new Error(`Websocket to proposer has failed`);
+  }
+  logger.debug('Rollback completed');
+  ws.send(JSON.stringify({ type: 'rollback', data }));
+}
+
 async function makeBlock(proposer, number = TRANSACTIONS_PER_BLOCK) {
   logger.debug('Block Assembler - about to make a new block');
   // we retrieve un-processed transactions from our local database, relying on
diff --git a/nightfall-optimist/src/services/block-utils.mjs b/nightfall-optimist/src/services/block-utils.mjs
new file mode 100644
index 000000000..dd9830b27
--- /dev/null
+++ b/nightfall-optimist/src/services/block-utils.mjs
@@ -0,0 +1,39 @@
+import constants from 'common-files/constants/index.mjs';
+import Web3 from 'web3';
+
+// These functions are called by static methods in the Block class but are sometimes needed when the rest
+// of the block object isn't.  They can thus be called directly when instantiating the Block class
+// would be problematic because of its reliance on the Optimist database.
+
+const { BLOCK_TYPES } = constants;
+
+export function calcBlockHash(block) {
+  const web3 = new Web3();
+  const { proposer, root, leafCount, blockNumberL2, previousBlockHash, transactionHashesRoot } =
+    block;
+  const blockArray = [
+    leafCount,
+    proposer,
+    root,
+    blockNumberL2,
+    previousBlockHash,
+    transactionHashesRoot,
+  ];
+  const encoded = web3.eth.abi.encodeParameters([BLOCK_TYPES], [blockArray]);
+  return web3.utils.soliditySha3({ t: 'bytes', v: encoded });
+}
+
+// remove properties that do not get sent to the blockchain returning
+// a new object (don't mutate the original)
+export function buildBlockSolidityStruct(block) {
+  const { proposer, root, leafCount, blockNumberL2, previousBlockHash, transactionHashesRoot } =
+    block;
+  return {
+    leafCount: Number(leafCount),
+    proposer,
+    root,
+    blockNumberL2: Number(blockNumberL2),
+    previousBlockHash,
+    transactionHashesRoot,
+  };
+}
diff --git a/nightfall-optimist/src/services/challenges.mjs b/nightfall-optimist/src/services/challenges.mjs
index 5a683bde4..429137726 100644
--- a/nightfall-optimist/src/services/challenges.mjs
+++ b/nightfall-optimist/src/services/challenges.mjs
@@ -33,7 +33,11 @@ export function stopMakingChallenges() {
   makeChallenges = false;
 }
 
-async function commitToChallenge(txDataToSign) {
+export async function commitToChallenge(txDataToSign) {
+  if (!makeChallenges) {
+    logger.debug('makeChallenges is off, no challenge commitment was sent');
+    return;
+  }
   const web3 = Web3.connection();
   const commitHash = web3.utils.soliditySha3({ t: 'bytes', v: txDataToSign });
   const challengeContractInstance = await getContractInstance(CHALLENGES_CONTRACT_NAME);
@@ -61,8 +65,8 @@ async function commitToChallenge(txDataToSign) {
   );
 }
 
-export async function revealChallenge(txDataToSign) {
-  logger.debug('raw challenge transaction has been sent to be signed and submitted');
+export async function revealChallenge(txDataToSign, sender) {
+  logger.debug('Revealing challenge');
   // check that the websocket exists (it should) and its readyState is OPEN
   // before sending commit. If not wait until the challenger reconnects
   let tryCount = 0;
@@ -73,181 +77,175 @@ export async function revealChallenge(txDataToSign) {
     );
     if (tryCount++ > 100) throw new Error(`Websocket to $challenger has failed`);
   }
-  ws.send(JSON.stringify({ type: 'challenge', txDataToSign }));
+  ws.send(JSON.stringify({ type: 'challenge', txDataToSign, sender }));
 }
 
 export async function createChallenge(block, transactions, err) {
   let txDataToSign;
-  if (makeChallenges) {
-    const challengeContractInstance = await getContractInstance(CHALLENGES_CONTRACT_NAME);
-    const salt = (await rand(32)).hex(32);
-    switch (err.code) {
-      // challenge incorrect leaf count
-      case 0: {
-        const priorBlockL2 = await getBlockByBlockNumberL2(block.blockNumberL2 - 1);
-        const priorBlockTransactions = await getTransactionsByTransactionHashes(
-          priorBlockL2.transactionHashes,
-        );
-        txDataToSign = await challengeContractInstance.methods
-          .challengeLeafCountCorrect(
-            Block.buildSolidityStruct(priorBlockL2), // the block immediately prior to this one
-            priorBlockTransactions.map(t => Transaction.buildSolidityStruct(t)), // the transactions in the prior block
-            Block.buildSolidityStruct(block),
-            transactions.map(t => Transaction.buildSolidityStruct(t)),
-            salt,
-          )
-          .encodeABI();
-        break;
-      }
-      // Challenge wrong root
-      case 1: {
-        logger.debug('Challenging incorrect root');
-        // Getting prior block for the current block
-        const priorBlock = await getBlockByBlockNumberL2(Number(block.blockNumberL2) - 1);
-        if (priorBlock === null)
-          throw new Error(
-            `Could not find prior block with block number ${Number(block.blockNumberL2) - 1}`,
-          );
-        // Retrieve last transaction from prior block using its transaction hash.
-        // Note that not all transactions in a block will have commitments. Loop until one is found
-        const priorBlockTransactions = await getTransactionsByTransactionHashes(
-          priorBlock.transactionHashes,
+  const challengeContractInstance = await getContractInstance(CHALLENGES_CONTRACT_NAME);
+  const salt = (await rand(32)).hex(32);
+  switch (err.code) {
+    // challenge incorrect leaf count
+    case 0: {
+      const priorBlockL2 = await getBlockByBlockNumberL2(block.blockNumberL2 - 1);
+      const priorBlockTransactions = await getTransactionsByTransactionHashes(
+        priorBlockL2.transactionHashes,
+      );
+      txDataToSign = await challengeContractInstance.methods
+        .challengeLeafCountCorrect(
+          Block.buildSolidityStruct(priorBlockL2), // the block immediately prior to this one
+          priorBlockTransactions.map(t => Transaction.buildSolidityStruct(t)), // the transactions in the prior block
+          Block.buildSolidityStruct(block),
+          transactions.map(t => Transaction.buildSolidityStruct(t)),
+          salt,
+        )
+        .encodeABI();
+      break;
+    }
+    // Challenge wrong root
+    case 1: {
+      logger.debug('Challenging incorrect root');
+      // Getting prior block for the current block
+      const priorBlock = await getBlockByBlockNumberL2(Number(block.blockNumberL2) - 1);
+      if (priorBlock === null)
+        throw new Error(
+          `Could not find prior block with block number ${Number(block.blockNumberL2) - 1}`,
         );
+      // Retrieve last transaction from prior block using its transaction hash.
+      // Note that not all transactions in a block will have commitments. Loop until one is found
+      const priorBlockTransactions = await getTransactionsByTransactionHashes(
+        priorBlock.transactionHashes,
+      );
 
-        // We also need to grab the block 2 before the challenged block as it contains the frontier to
-        // calculate the root of the prior block.
-        const priorPriorBlock = await getBlockByBlockNumberL2(Number(block.blockNumberL2) - 2);
-        if (priorPriorBlock === null) priorPriorBlock.root = ZERO;
+      // We also need to grab the block 2 before the challenged block as it contains the frontier to
+      // calculate the root of the prior block.
+      const priorPriorBlock = await getBlockByBlockNumberL2(Number(block.blockNumberL2) - 2);
+      if (priorPriorBlock === null) priorPriorBlock.root = ZERO;
 
-        const priorPriorTree = await getTreeByRoot(priorPriorBlock.root);
-        // We need to pad our frontier as we don't store them with the trailing zeroes.
-        const frontierToValidatePreviousBlock = priorPriorTree.frontier.concat(
-          Array(TIMBER_HEIGHT - priorPriorTree.frontier.length + 1).fill(ZERO),
-        );
-        // Create a challenge
-        txDataToSign = await challengeContractInstance.methods
-          .challengeNewRootCorrect(
-            Block.buildSolidityStruct(priorBlock),
-            priorBlockTransactions.map(t => Transaction.buildSolidityStruct(t)),
-            frontierToValidatePreviousBlock,
-            Block.buildSolidityStruct(block),
-            transactions.map(t => Transaction.buildSolidityStruct(t)),
-            salt,
-          )
-          .encodeABI();
-        break;
-      }
-      // challenge duplicate commitment
-      case 2: {
-        const {
-          block1,
-          transactions1,
+      const priorPriorTree = await getTreeByRoot(priorPriorBlock.root);
+      // We need to pad our frontier as we don't store them with the trailing zeroes.
+      const frontierToValidatePreviousBlock = priorPriorTree.frontier.concat(
+        Array(TIMBER_HEIGHT - priorPriorTree.frontier.length + 1).fill(ZERO),
+      );
+      // Create a challenge
+      txDataToSign = await challengeContractInstance.methods
+        .challengeNewRootCorrect(
+          Block.buildSolidityStruct(priorBlock),
+          priorBlockTransactions.map(t => Transaction.buildSolidityStruct(t)),
+          frontierToValidatePreviousBlock,
+          Block.buildSolidityStruct(block),
+          transactions.map(t => Transaction.buildSolidityStruct(t)),
+          salt,
+        )
+        .encodeABI();
+      break;
+    }
+    // challenge duplicate commitment
+    case 2: {
+      const {
+        block1,
+        transactions1,
+        transaction1Index,
+        duplicateCommitment1Index,
+        block2,
+        transactions2,
+        transaction2Index,
+        duplicateCommitment2Index,
+      } = err.metadata;
+      txDataToSign = await challengeContractInstance.methods
+        .challengeCommitment(
+          Block.buildSolidityStruct(block1),
+          Block.buildSolidityStruct(block2),
+          transactions1.map(t => Transaction.buildSolidityStruct(t)),
+          transactions2.map(t => Transaction.buildSolidityStruct(t)),
           transaction1Index,
-          duplicateCommitment1Index,
-          block2,
-          transactions2,
           transaction2Index,
+          duplicateCommitment1Index,
           duplicateCommitment2Index,
-        } = err.metadata;
-        txDataToSign = await challengeContractInstance.methods
-          .challengeCommitment(
-            Block.buildSolidityStruct(block1),
-            Block.buildSolidityStruct(block2),
-            transactions1.map(t => Transaction.buildSolidityStruct(t)),
-            transactions2.map(t => Transaction.buildSolidityStruct(t)),
-            transaction1Index,
-            transaction2Index,
-            duplicateCommitment1Index,
-            duplicateCommitment2Index,
-            salt,
-          )
-          .encodeABI();
-        break;
-      }
-      // challenge duplicate nullifier
-      case 3: {
-        const {
-          block1,
-          transactions1,
+          salt,
+        )
+        .encodeABI();
+      break;
+    }
+    // challenge duplicate nullifier
+    case 3: {
+      const {
+        block1,
+        transactions1,
+        transaction1Index,
+        duplicateNullifier1Index,
+        block2,
+        transactions2,
+        transaction2Index,
+        duplicateNullifier2Index,
+      } = err.metadata;
+      txDataToSign = await challengeContractInstance.methods
+        .challengeNullifier(
+          Block.buildSolidityStruct(block1),
+          Block.buildSolidityStruct(block2),
+          transactions1.map(t => Transaction.buildSolidityStruct(t)),
+          transactions2.map(t => Transaction.buildSolidityStruct(t)),
           transaction1Index,
-          duplicateNullifier1Index,
-          block2,
-          transactions2,
           transaction2Index,
+          duplicateNullifier1Index,
           duplicateNullifier2Index,
-        } = err.metadata;
-        txDataToSign = await challengeContractInstance.methods
-          .challengeNullifier(
-            Block.buildSolidityStruct(block1),
-            Block.buildSolidityStruct(block2),
-            transactions1.map(t => Transaction.buildSolidityStruct(t)),
-            transactions2.map(t => Transaction.buildSolidityStruct(t)),
-            transaction1Index,
-            transaction2Index,
-            duplicateNullifier1Index,
-            duplicateNullifier2Index,
-            salt,
-          )
-          .encodeABI();
-        break;
-      }
-      // proof does not verify
-      case 4: {
-        const { transactionHashIndex: transactionIndex } = err.metadata;
-        // Create a challenge
-        const uncompressedProof = transactions[transactionIndex].proof;
-        const [historicInput1, historicInput2, historicInput3, historicInput4] = await Promise.all(
-          transactions[transactionIndex].historicRootBlockNumberL2.map(async (b, i) => {
-            if (transactions[transactionIndex].nullifiers[i] === 0) {
-              return {
-                historicBlock: {},
-                historicTxs: [],
-              };
-            }
-            const historicBlock = await getBlockByBlockNumberL2(b);
-            const historicTxs = await getTransactionsByTransactionHashes(block.transactionHashes);
+          salt,
+        )
+        .encodeABI();
+      break;
+    }
+    // proof does not verify
+    case 4: {
+      const { transactionHashIndex: transactionIndex } = err.metadata;
+      // Create a challenge
+      const uncompressedProof = transactions[transactionIndex].proof;
+      const [historicInput1, historicInput2, historicInput3, historicInput4] = await Promise.all(
+        transactions[transactionIndex].historicRootBlockNumberL2.map(async (b, i) => {
+          if (transactions[transactionIndex].nullifiers[i] === 0) {
             return {
-              historicBlock: Block.buildSolidityStruct(historicBlock),
-              historicTxs,
+              historicBlock: {},
+              historicTxs: [],
             };
-          }),
-        );
+          }
+          const historicBlock = await getBlockByBlockNumberL2(b);
+          const historicTxs = await getTransactionsByTransactionHashes(block.transactionHashes);
+          return {
+            historicBlock: Block.buildSolidityStruct(historicBlock),
+            historicTxs,
+          };
+        }),
+      );
 
-        txDataToSign = await challengeContractInstance.methods
-          .challengeProofVerification(
-            Block.buildSolidityStruct(block),
-            transactions.map(t => Transaction.buildSolidityStruct(t)),
-            transactionIndex,
-            [
-              historicInput1.historicBlock,
-              historicInput2.historicBlock,
-              historicInput3.historicBlock,
-              historicInput4.historicBlock,
-            ],
-            [
-              historicInput1.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
-              historicInput2.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
-              historicInput3.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
-              historicInput4.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
-            ],
-            uncompressedProof,
-            salt,
-          )
-          .encodeABI();
-        break;
-      }
-      default:
-      // code block
+      txDataToSign = await challengeContractInstance.methods
+        .challengeProofVerification(
+          Block.buildSolidityStruct(block),
+          transactions.map(t => Transaction.buildSolidityStruct(t)),
+          transactionIndex,
+          [
+            historicInput1.historicBlock,
+            historicInput2.historicBlock,
+            historicInput3.historicBlock,
+            historicInput4.historicBlock,
+          ],
+          [
+            historicInput1.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
+            historicInput2.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
+            historicInput3.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
+            historicInput4.historicTxs.map(t => Transaction.buildSolidityStruct(t)),
+          ],
+          uncompressedProof,
+          salt,
+        )
+        .encodeABI();
+      break;
     }
-    // now we need to commit to this challenge. When we have, this fact will be
-    // picked up by the challenge-commit event-handler and a reveal will be sent
-    // to intiate the challenge transaction (after checking we haven't been
-    // front-run)
-    commitToChallenge(txDataToSign);
-  } else {
-    // only proposer not a challenger
-    logger.info(
-      "Faulty block detected. Don't submit new blocks until the faulty blocks are removed",
-    );
+    default:
+    // code block
   }
+  // now we need to commit to this challenge. When we have, this fact will be
+  // picked up by the challenge-commit event-handler and a reveal will be sent
+  // to intiate the challenge transaction (after checking we haven't been
+  // front-run)
+  logger.info("Faulty block detected. Don't submit new blocks until the faulty blocks are removed");
+  return txDataToSign;
 }
diff --git a/nightfall-optimist/src/services/database.mjs b/nightfall-optimist/src/services/database.mjs
index 3c1360af3..f5c580b08 100644
--- a/nightfall-optimist/src/services/database.mjs
+++ b/nightfall-optimist/src/services/database.mjs
@@ -16,7 +16,6 @@ const {
   OPTIMIST_DB,
   TRANSACTIONS_COLLECTION,
   PROPOSER_COLLECTION,
-  CHALLENGER_COLLECTION,
   SUBMITTED_BLOCKS_COLLECTION,
   INVALID_BLOCKS_COLLECTION,
   COMMIT_COLLECTION,
@@ -48,43 +47,6 @@ export async function getCommit(commitHash) {
   return commit;
 }
 
-/**
-function to store addresses that are used to sign challenge transactions.  This
-is done so that we can check that a challenge commit is from us and hasn't been
-front-run (because that would change the origin address of the commit to that of
-the front-runner).
-*/
-export async function addChallengerAddress(address) {
-  const connection = await mongo.connection(MONGO_URL);
-  const db = connection.db(OPTIMIST_DB);
-  logger.debug(`Saving challenger address ${address}`);
-  const data = { challenger: address };
-  return db.collection(CHALLENGER_COLLECTION).insertOne(data);
-}
-
-/**
-function to remove addresses that are used to sign challenge transactions. This
-is needed in the case of a key compromise, or if we simply no longer wish to use
-the address.
-*/
-export async function removeChallengerAddress(address) {
-  const connection = await mongo.connection(MONGO_URL);
-  const db = connection.db(OPTIMIST_DB);
-  logger.debug(`Removing challenger address ${address}`);
-  const data = { challenger: address };
-  return db.collection(CHALLENGER_COLLECTION).deleteOne(data);
-}
-
-/**
-Function to tell us if an address used to commit to a challenge belongs to us
-*/
-export async function isChallengerAddressMine(address) {
-  const connection = await mongo.connection(MONGO_URL);
-  const db = connection.db(OPTIMIST_DB);
-  const metadata = await db.collection(CHALLENGER_COLLECTION).findOne({ challenger: address });
-  return metadata !== null;
-}
-
 /**
 function to save a block, so that we can later search the block, for example to
 find which block a transaction went into. Note, we'll save all blocks, that get
diff --git a/nightfall-optimist/src/services/state-sync.mjs b/nightfall-optimist/src/services/state-sync.mjs
index 70bf2d9fc..58f16b764 100644
--- a/nightfall-optimist/src/services/state-sync.mjs
+++ b/nightfall-optimist/src/services/state-sync.mjs
@@ -1,8 +1,9 @@
 /* eslint-disable no-await-in-loop */
 
 import { getContractInstance } from 'common-files/utils/contract.mjs';
-import { pauseQueue, unpauseQueue } from 'common-files/utils/event-queue.mjs';
 import constants from 'common-files/constants/index.mjs';
+import { pauseQueue, unpauseQueue, queues, flushQueue } from 'common-files/utils/event-queue.mjs';
+import logger from 'common-files/utils/logger.mjs';
 import blockProposedEventHandler from '../event-handlers/block-proposed.mjs';
 import transactionSubmittedEventHandler from '../event-handlers/transaction-submitted.mjs';
 import newCurrentProposerEventHandler from '../event-handlers/new-current-proposer.mjs';
@@ -46,7 +47,6 @@ const syncState = async (
     .sort((a, b) => a.blockNumber - b.blockNumber);
   for (let i = 0; i < splicedList.length; i++) {
     const pastEvent = splicedList[i];
-    console.log('PAST EVENT', pastEvent);
     switch (pastEvent.event) {
       case 'NewCurrentProposer':
         await newCurrentProposerEventHandler(pastEvent, [proposer]);
@@ -107,10 +107,12 @@ export default async proposer => {
   if (lastBlockNumberL2 === -1) {
     unpauseQueue(0); // queues are started paused, therefore we need to unpause them before proceeding.
     unpauseQueue(1);
+    startMakingChallenges();
     return null; // The blockchain is empty
   }
   // pause the queues so we stop processing incoming events while we sync
   await Promise.all([pauseQueue(0), pauseQueue(1)]);
+  logger.info('Begining synchronisation with the blockchain');
   const missingBlocks = await checkBlocks(); // Stores any gaps of missing blocks
   // const [fromBlock] = missingBlocks[0];
   const latestBlockLocally = (await getBlockByBlockNumberL2(lastBlockNumberL2)) ?? undefined;
@@ -121,10 +123,26 @@ export default async proposer => {
     for (let i = 0; i < missingBlocks.length; i++) {
       const [fromBlock, toBlock] = missingBlocks[i];
       // Sync the state inbetween these blocks
-
       await syncState(proposer, fromBlock, toBlock);
     }
+    // at this point, we have synchronised all the existing blocks. If there are no outstanding
+    // challenges (all rollbacks have completed) then we're done.  It's possible however that
+    // we had a bad block that was not rolled back. If this is the case then there will still be
+    // a challenge in the stop queue that was not removed by a rollback.
+    // If this is the case we'll run the stop queue to challenge the bad block.
     await startMakingChallenges();
+    if (queues[2].length === 0)
+      logger.info('After synchronisation, no challenges remain unresolved');
+    else {
+      logger.info(
+        `After synchronisation, there were ${queues[2].length} unresolved challenges.  Running them now.`,
+      );
+      // start queue[2] and await all the unresolved challenges being run
+      const p = flushQueue(2);
+      queues[2].start();
+      await p;
+      logger.debug('All challenges in the stop queue have now been made.');
+    }
   }
   const currentProposer = (await stateContractInstance.methods.currentProposer().call())
     .thisAddress;
diff --git a/package.json b/package.json
index 36b0453d6..38b7423e7 100644
--- a/package.json
+++ b/package.json
@@ -10,13 +10,14 @@
     "build-adversary": "node test/adversary/transpile-adversary.mjs",
     "test": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/protocol/*.test.mjs test/e2e/tokens/*.test.mjs",
     "test-e2e-protocol": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/protocol/*.test.mjs ",
-    "test-gas": "mocha --timeout 0 --bail --exit test/e2e/gas.test.mjs ",
-    "test-circuits": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/circuits.test.mjs ",
+    "test-gas": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/gas.test.mjs ",
+    "test-circuits": "LOG_LEVEL=debug mocha --timeout 0 --bail --exit test/e2e/circuits.test.mjs ",
     "test-e2e-tokens": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/tokens/*.test.mjs ",
     "test-erc20-tokens": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/tokens/erc20.test.mjs ",
     "test-erc721-tokens": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/tokens/erc721.test.mjs ",
     "test-erc1155-tokens": "LOG_LEVEL=error mocha --timeout 0 --bail --exit test/e2e/tokens/erc1155.test.mjs ",
     "test-erc20-cli": "LOG_LEVEL=debug mocha --timeout 0 --bail --exit test/client/erc20.test.mjs ",
+    "test-optimist-sync": "LOG_LEVEL=silent mocha --timeout 0 --bail --exit test/optimist-resync.test.mjs",
     "test-adversary": "CHALLENGE_TYPE=${CHALLENGE_TYPE} mocha --timeout 0 --bail --exit test/adversary.test.mjs",
     "test-all-adversary": "for CHALLENGE_TYPE in IncorrectTreeRoot IncorrectLeafCount IncorrectTreeRoot IncorrectLeafCount; do CHALLENGE_TYPE=${CHALLENGE_TYPE} mocha --timeout 0 --bail --exit test/adversary.test.mjs; sleep 5; done",
     "test-general-stuff": "LOG_LEVEL=debug mocha --timeout 0 --bail --exit test/kem-dem.test.mjs test/timber.test.mjs"
diff --git a/setup-nightfall b/setup-nightfall
index 8b42d92dc..7bb6ddd43 100755
--- a/setup-nightfall
+++ b/setup-nightfall
@@ -1,15 +1,13 @@
 #! /bin/bash
+set -e
 
 # Install node dependencies
 npm ci
-
-OS_ARCH=$(uname -m)
-NO_CACHE_FLAG=''
-
-# Workaround when building in a Mac
-if [ $OS_ARCH != "x86_64" ]; then
-  NO_CACHE_FLAG='--no-cache'
-fi
-
-docker build ${NO_CACHE_FLAG} -t ghcr.io/eyblockchain/local-zokrates:0.7.13 -f zokrates.Dockerfile .
-docker-compose -f docker-compose.yml -f docker-compose.dev.yml build ${NO_CACHE_FLAG}
+docker build -t ghcr.io/eyblockchain/local-zokrates:0.7.13 -f zokrates.Dockerfile .
+# containers built separately. A parallel build fails.
+docker-compose -f docker-compose.yml -f docker-compose.dev.yml build administrator
+docker-compose -f docker-compose.yml -f docker-compose.dev.yml build client
+docker-compose -f docker-compose.yml -f docker-compose.dev.yml build optimist
+docker-compose -f docker-compose.yml -f docker-compose.dev.yml build worker
+docker-compose -f docker-compose.yml -f docker-compose.dev.yml build hosted-utils-api-server
+docker-compose -f docker-compose.yml -f docker-compose.dev.yml -f docker-compose.adversary.yml build adversary1
diff --git a/start-nightfall b/start-nightfall
index 95001e666..46e67ada6 100755
--- a/start-nightfall
+++ b/start-nightfall
@@ -56,9 +56,9 @@ trap "docker-compose $FILE $STUBS $DEV $ADVERSARY down --remove-orphans -t 1; ex
 docker-compose -f docker-compose.yml $FILE $STUBS $DEV $ADVERSARY down --remove-orphans
 
 # if-else block checks - volume exist and then removes it.
-if [[ $(echo $VOLUME_LIST | grep nightfall_3_mongodb1) ]]; then
+if [[ $(echo $VOLUME_LIST | grep nightfall_3_mongodb) ]]; then
   echo -n 'Removing '
-  docker volume rm nightfall_3_mongodb1
+  docker volume rm nightfall_3_mongodb
 fi
 
 if [[ $(echo $VOLUME_LIST | grep nightfall_3_mongodb2) ]]; then
@@ -92,4 +92,4 @@ if [[ -d "$DIR" ]]; then
 fi
 #docker-compose -f docker-compose.yml $FILE up -d deployer
 docker-compose $FILE $STUBS $DEV $ADVERSARY up -d --remove-orphans
-docker-compose logs -f client1 optimist1 worker deployer
+docker-compose logs -f client optimist worker deployer
diff --git a/test/adversary.test.mjs b/test/adversary.test.mjs
index 5717f1153..7df67041a 100644
--- a/test/adversary.test.mjs
+++ b/test/adversary.test.mjs
@@ -120,8 +120,6 @@ describe('Testing with an adversary', () => {
       registerProposerOnNoProposer(nf3AdversarialProposer);
     }, 5000);
 
-    // Challenger registration
-    await nf3Challenger.registerChallenger();
     // Chalenger listening for incoming events
     const challengeEmitter = await nf3Challenger.startChallenger();
     challengeEmitter
@@ -170,7 +168,7 @@ describe('Testing with an adversary', () => {
         nDeposits++;
         expectedBalance += value2;
       }
-
+      console.log('Number of deposits', nDeposits);
       for (let i = 0; i < TEST_LENGTH; i++) {
         await waitForSufficientBalance(
           nf3User,
@@ -209,11 +207,13 @@ describe('Testing with an adversary', () => {
             nTransfers++;
           }
         }
+        console.log('Number of transfers', nTransfers);
         for (let k = 0; k < TRANSACTIONS_PER_BLOCK - 1; k++) {
           await nf3User.deposit(ercAddress, tokenType, value2, tokenId, fee);
           nDeposits++;
           expectedBalance += value2;
         }
+        console.log('Number of deposits', nDeposits);
         await new Promise(resolve => setTimeout(resolve, TX_WAIT)); // this may need to be longer on a real blockchain
         console.log(`Completed ${i + 1} pings with expectedBalance ${expectedBalance}`);
       }
diff --git a/test/adversary/transpile-adversary.mjs b/test/adversary/transpile-adversary.mjs
index dcdd8cca7..8ad5b08e0 100644
--- a/test/adversary/transpile-adversary.mjs
+++ b/test/adversary/transpile-adversary.mjs
@@ -43,11 +43,10 @@ const transpileBlockProposed = _pathToSrc => {
   let srcFile = fs.readFileSync(_pathToSrc, 'utf-8');
 
   // We need to take into account variable NONSTOP_QUEUE_AFTER_INVALID_BLOCK
-  const regexReplaceComponents =
-    /(await enqueueEvent\(\(\) => logger.info\('Stop Until Rollback'\), 2\);)/g;
+  const regexReplaceComponents = /(await enqueueEvent\(commitToChallenge, 2, txDataToSign\);)/g;
   const reComponent = `logger.info(\`NONSTOP_QUEUE_AFTER_INVALID_BLOCK: \${process.env.NONSTOP_QUEUE_AFTER_INVALID_BLOCK}\`);
-      if (process.env.NONSTOP_QUEUE_AFTER_INVALID_BLOCK === "false")
-           await enqueueEvent(() => logger.info('Stop Until Rollback'), 2);`;
+      if (!process.env.NONSTOP_QUEUE_AFTER_INVALID_BLOCK === "false")
+         await enqueueEvent(commitToChallenge, 2, txDataToSign);`;
   srcFile = `/* THIS FILE CONTAINS CODE THAT HAS BEEN AUTOGENERATED DO NOT MODIFY MANUALLY */\n${srcFile.replace(
     regexReplaceComponents,
     reComponent,
diff --git a/test/e2e/circuits.test.mjs b/test/e2e/circuits.test.mjs
index b334e6403..1860c8524 100644
--- a/test/e2e/circuits.test.mjs
+++ b/test/e2e/circuits.test.mjs
@@ -144,7 +144,7 @@ describe('General Circuit Test', () => {
 
     await nf3Users[0].makeBlockNow();
 
-    eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+    ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
 
     logger.debug(`Sending withdrawal with no change...`);
     const withdrawalNoChange = await nf3Users[0].withdraw(
diff --git a/test/e2e/gas.test.mjs b/test/e2e/gas.test.mjs
index 97db948e4..fc15c78fd 100644
--- a/test/e2e/gas.test.mjs
+++ b/test/e2e/gas.test.mjs
@@ -82,7 +82,7 @@ describe('Gas test', () => {
         tokenId,
         0,
       );
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
 
       expect(gasCost).to.be.lessThan(expectedGasCostPerTx);
     });
@@ -97,7 +97,7 @@ describe('Gas test', () => {
         tokenId,
         0,
       );
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
       expect(gasCost).to.be.lessThan(expectedGasCostPerTx);
       console.log('Deposit L1 average gas used was', averageL1GasCost(receipts));
     });
@@ -116,7 +116,7 @@ describe('Gas test', () => {
         nf3Users[0].zkpKeys.compressedZkpPublicKey,
         0,
       );
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
       expect(gasCost).to.be.lessThan(expectedGasCostPerTx);
       console.log(
         'Single transfer L1 average gas used, if on-chain, was',
@@ -138,7 +138,7 @@ describe('Gas test', () => {
         nf3Users[0].zkpKeys.compressedZkpPublicKey,
         0,
       );
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
       expect(gasCost).to.be.lessThan(expectedGasCostPerTx);
       console.log(
         'Double transfer L1 average gas used, if on-chain, was',
@@ -161,7 +161,7 @@ describe('Gas test', () => {
         0,
       );
       await nf3Users[0].makeBlockNow();
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
       expect(gasCost).to.be.lessThan(expectedGasCostPerTx);
       console.log('Withdraw L1 average gas used, if on-chain, was', averageL1GasCost(receipts));
     });
diff --git a/test/e2e/protocol/challenger.test.mjs b/test/e2e/protocol/challenger.test.mjs
deleted file mode 100644
index 14890b6f5..000000000
--- a/test/e2e/protocol/challenger.test.mjs
+++ /dev/null
@@ -1,40 +0,0 @@
-/* eslint-disable no-await-in-loop */
-import chai from 'chai';
-import config from 'config';
-import chaiHttp from 'chai-http';
-import chaiAsPromised from 'chai-as-promised';
-import Nf3 from '../../../cli/lib/nf3.mjs';
-
-// so we can use require with mjs file
-const { expect } = chai;
-chai.use(chaiHttp);
-chai.use(chaiAsPromised);
-
-const environment = config.ENVIRONMENTS[process.env.ENVIRONMENT] || config.ENVIRONMENTS.localhost;
-
-const { signingKeys } = config.RESTRICTIONS;
-const { mnemonics } = config.TEST_OPTIONS;
-
-const bootChallenger = new Nf3(signingKeys.bootChallengerKey, environment);
-
-describe('Basic Challenger tests', () => {
-  before(async () => {
-    await bootChallenger.init(mnemonics.challenger);
-  });
-
-  it('should register the boot challenger', async () => {
-    // Challenger registration
-    await bootChallenger.registerChallenger();
-    // Chalenger listening for incoming events
-    bootChallenger.startChallenger();
-  });
-
-  it('should de-register a challenger', async () => {
-    const res = await bootChallenger.deregisterChallenger();
-    expect(res.status).to.be.equal(200);
-  });
-
-  after(async () => {
-    await bootChallenger.close();
-  });
-});
diff --git a/test/e2e/tokens/erc20.test.mjs b/test/e2e/tokens/erc20.test.mjs
index cfbf12c2f..bd8de3bb4 100644
--- a/test/e2e/tokens/erc20.test.mjs
+++ b/test/e2e/tokens/erc20.test.mjs
@@ -27,7 +27,7 @@ const {
 
 const {
   RESTRICTIONS: {
-    tokens: { blockchain1: maxWithdrawValue },
+    tokens: { blockchain: maxWithdrawValue },
   },
 } = config;
 
@@ -65,7 +65,7 @@ describe('ERC20 tests', () => {
   before(async () => {
     await nf3Proposer.init(mnemonics.proposer);
     // we must set the URL from the point of view of the client container
-    await nf3Proposer.registerProposer('http://optimist1');
+    await nf3Proposer.registerProposer('http://optimist');
 
     // Proposer listening for incoming events
     const newGasBlockEmitter = await nf3Proposer.startProposer();
diff --git a/test/optimist-resync.test.mjs b/test/optimist-resync.test.mjs
new file mode 100644
index 000000000..83522dad2
--- /dev/null
+++ b/test/optimist-resync.test.mjs
@@ -0,0 +1,235 @@
+/* eslint-disable no-await-in-loop */
+import chai from 'chai';
+import chaiHttp from 'chai-http';
+import chaiAsPromised from 'chai-as-promised';
+import config from 'config';
+import compose from 'docker-compose';
+import constants from 'common-files/constants/index.mjs';
+import Transaction from 'common-files/classes/transaction.mjs';
+import logger from 'common-files/utils/logger.mjs';
+import Nf3 from '../cli/lib/nf3.mjs';
+import { depositNTransactions, Web3Client } from './utils.mjs';
+import { buildBlockSolidityStruct } from '../nightfall-optimist/src/services/block-utils.mjs';
+// so we can use require with mjs file
+const { expect } = chai;
+chai.use(chaiHttp);
+chai.use(chaiAsPromised);
+
+const environment = config.ENVIRONMENTS[process.env.ENVIRONMENT] || config.ENVIRONMENTS.localhost;
+
+const {
+  fee,
+  transferValue,
+  txPerBlock,
+  tokenConfigs: { tokenType, tokenId },
+  mnemonics,
+  signingKeys,
+} = config.TEST_OPTIONS;
+
+const { PROPOSE_BLOCK_TYPES } = constants;
+
+const nf3Users = [new Nf3(signingKeys.user1, environment), new Nf3(signingKeys.user2, environment)];
+const nf3Proposer1 = new Nf3(signingKeys.proposer1, environment);
+const nf3Challenger = new Nf3(signingKeys.challenger, environment);
+
+const web3Client = new Web3Client();
+
+let erc20Address;
+let stateAddress;
+let eventLogs = [];
+let eventsSeen;
+
+describe('Optimist synchronisation tests', () => {
+  let blockProposeEmitter;
+  let challengeEmitter;
+  const options = {
+    config: ['docker-compose.yml', 'docker-compose.dev.yml', 'docker-compose.ganache.yml'],
+    log: process.env.LOG_LEVEL !== 'silent',
+  };
+
+  before(async () => {
+    await nf3Proposer1.init(mnemonics.proposer);
+    await nf3Challenger.init(mnemonics.challenger);
+    // we must set the URL from the point of view of the client container
+    await nf3Proposer1.registerProposer('http://optimist');
+
+    // Proposer listening for incoming events
+    blockProposeEmitter = await nf3Proposer1.startProposer();
+    challengeEmitter = await nf3Challenger.startChallenger();
+    challengeEmitter.on('receipt', (receipt, type) =>
+      logger.debug(`challenge listener received challenge receipt of type ${type}`),
+    );
+    challengeEmitter.on('error', (err, type) =>
+      logger.debug(`challenge listener received error ${err.message} of type ${type}`),
+    );
+    await nf3Users[0].init(mnemonics.user1);
+    await nf3Users[1].init(mnemonics.user2);
+    erc20Address = await nf3Users[0].getContractAddress('ERC20Mock');
+
+    stateAddress = await nf3Users[0].stateContractAddress;
+    web3Client.subscribeTo('logs', eventLogs, { address: stateAddress });
+  });
+
+  describe('With and without a bad block', () => {
+    // setup a listener for a block proposal
+    const proposePromise = () =>
+      new Promise(resolve =>
+        blockProposeEmitter.on('receipt', (receipt, b, t) =>
+          resolve({ receipt, block: b, transactions: t }),
+        ),
+      );
+    // setup a listener for a block proposal
+    const rollbackPromise = () =>
+      new Promise(resolve => blockProposeEmitter.on('rollback', () => resolve()));
+
+    // setup a healthcheck wait
+    const healthy = async () => {
+      while (!(await nf3Proposer1.healthcheck('optimist'))) {
+        await new Promise(resolve => setTimeout(resolve, 1000));
+      }
+      logger.debug('optimist is healthy');
+    };
+
+    it('Resync optimist after making a good block', async function () {
+      // We create enough good transactions to fill a block full of deposits.
+      logger.debug(`      Sending ${txPerBlock} deposits...`);
+      let p = proposePromise();
+      await depositNTransactions(
+        nf3Users[0],
+        txPerBlock,
+        erc20Address,
+        tokenType,
+        transferValue,
+        tokenId,
+        fee,
+      );
+      // we can use the emitter that nf3 provides to get the block and transactions we've just made.
+      // The promise resolves once the block is on-chain.
+      const { block } = await p;
+      const firstBlock = { ...block };
+      // we still need to clean the 'BlockProposed' event from the  test logs though.
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
+      // Now we have a block, let's force Optimist to re-sync by turning it off and on again!
+      await compose.stopOne('optimist', options);
+      await compose.rm(options, 'optimist');
+      await compose.upOne('optimist', options);
+      await healthy();
+
+      // we need to remind optimist which proposer it's connected to
+      await nf3Proposer1.registerProposer('http://optimist');
+      // TODO - get optimist to do this automatically.
+      // Now we'll add another block and check that it's blocknumber is correct, indicating
+      // that a resync correctly occured
+      logger.debug(`      Sending ${txPerBlock} deposits...`);
+      p = proposePromise();
+      await depositNTransactions(
+        nf3Users[0],
+        txPerBlock,
+        erc20Address,
+        tokenType,
+        transferValue,
+        tokenId,
+        fee,
+      );
+      // we can use the emitter that nf3 provides to get the block and transactions we've just made.
+      // The promise resolves once the block is on-chain.
+      const { block: secondBlock } = await p;
+      // we still need to clean the 'BlockProposed' event from the  test logs though.
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
+      expect(secondBlock.blockNumberL2 - firstBlock.blockNumberL2).to.equal(1);
+    });
+    it('Resync optimist after making an un-resolved bad block', async function () {
+      // We create enough good transactions to fill a block full of deposits.
+      logger.debug(`      Sending ${txPerBlock} deposits...`);
+      let p = proposePromise();
+      await depositNTransactions(
+        nf3Users[0],
+        txPerBlock,
+        erc20Address,
+        tokenType,
+        transferValue,
+        tokenId,
+        fee,
+      );
+      // we can use the emitter that nf3 provides to get the block and transactions we've just made.
+      // The promise resolves once the block is on-chain.
+      const { block, transactions } = await p;
+      const firstBlock = { ...block };
+      // we still need to clean the 'BlockProposed' event from the  test logs though.
+      ({ eventLogs, eventsSeen } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
+      // turn off challenging.  We're going to make a bad block and we don't want it challenged
+      await nf3Challenger.challengeEnable(false);
+      // update the block so we can submit it again
+      // we'll do the easiest thing and submit it again with no change other than to increment
+      // the L2 block number and block hash so that it doesn't get reverted straight away.
+      // It will be a bad block because we'll have submitted the same transactions and leafcount
+      // before.
+      // To achieve that, we'll manually assemble and submit a new proposeBlock call
+      // in the following lines...
+
+      // retrieve the code for the 'proposeBlock' function. We'll check it every time rather than
+      // hard code it, in case someone changes the function.
+      const functionCode = (
+        await web3Client.getWeb3().eth.getTransaction(eventsSeen[0].log.transactionHash)
+      ).input.slice(0, 10);
+      // fix up the blockHash and blockNumberL2 to prevent an immediate revert
+      block.previousBlockHash = block.blockHash;
+      block.blockNumberL2++;
+      // now assemble our bad-block transaction; first the parameters
+      const blockData = Object.values(buildBlockSolidityStruct(block));
+      const transactionsData = Object.values(
+        transactions.map(t => Object.values(Transaction.buildSolidityStruct(t))),
+      );
+      const encodedParams = web3Client
+        .getWeb3()
+        .eth.abi.encodeParameters(PROPOSE_BLOCK_TYPES, [blockData, transactionsData]);
+      // then the function identifier is added
+      const newTx = `${functionCode}${encodedParams.slice(2)}`;
+      // then send it!
+      logger.debug('Resubmitting the same transactions in the next block');
+      await web3Client.submitTransaction(newTx, signingKeys.proposer1, stateAddress, 8000000, 1);
+      logger.debug('bad block submitted');
+      const r = rollbackPromise();
+      // Now we have a bad block, let's force Optimist to re-sync by turning it off and on again!
+      await compose.stopOne('optimist', options);
+      await compose.rm(options, 'optimist');
+      await compose.upOne('optimist', options);
+      await healthy();
+
+      logger.debug('waiting for rollback to complete');
+      await r;
+      logger.debug('rollback complete event received');
+      // the rollback will have removed us as proposer. We need to re-register because we
+      // were the only proposer in town!
+      await nf3Proposer1.registerProposer('http://optimist');
+      // Now we'll add another block and check that it's blocknumber is correct, indicating
+      // that a rollback correctly occured
+      logger.debug(`      Sending ${txPerBlock} deposits...`);
+      p = proposePromise();
+      await depositNTransactions(
+        nf3Users[0],
+        txPerBlock,
+        erc20Address,
+        tokenType,
+        transferValue,
+        tokenId,
+        fee,
+      );
+      // we can use the emitter that nf3 provides to get the block and transactions we've just made.
+      // The promise resolves once the block is on-chain.
+      const { block: secondBlock } = await p;
+      // we still need to clean the 'BlockProposed' event from the  test logs though.
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
+      expect(secondBlock.blockNumberL2 - firstBlock.blockNumberL2).to.equal(1);
+    });
+  });
+
+  after(async () => {
+    await nf3Proposer1.deregisterProposer();
+    await nf3Proposer1.close();
+    await nf3Challenger.close();
+    await nf3Users[0].close();
+    await nf3Users[1].close();
+    await web3Client.closeWeb3();
+  });
+});
diff --git a/test/ping-pong/docker-compose.standalone.ganache.yml b/test/ping-pong/docker-compose.standalone.ganache.yml
index 9fd1d0449..83b7dd986 100644
--- a/test/ping-pong/docker-compose.standalone.ganache.yml
+++ b/test/ping-pong/docker-compose.standalone.ganache.yml
@@ -3,7 +3,7 @@ version: '3.5'
 # bindings and using a Ganache private blockchain.  See the readme for more information.
 # It acts as an override file for docker-compose.yml
 services:
-  blockchain1:
+  blockchain:
     image: trufflesuite/ganache-cli:v6.12.1
     ports:
       - 8546:8546
diff --git a/test/ping-pong/docker-compose.yml b/test/ping-pong/docker-compose.yml
index 85773d223..b61a62c12 100644
--- a/test/ping-pong/docker-compose.yml
+++ b/test/ping-pong/docker-compose.yml
@@ -22,7 +22,7 @@ services:
       MONGO_INITDB_ROOT_USERNAME: admin
       MONGO_INITDB_ROOT_PASSWORD: admin
       LOG_LEVEL: debug
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       ZOKRATES_WORKER_HOST: worker
       RABBITMQ_HOST: amqp://rabbitmq
@@ -53,7 +53,7 @@ services:
         target: /app/build/
     environment:
       WEBSOCKET_PORT: 8080
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       HASH_TYPE: poseidon
       LOG_LEVEL: debug
@@ -79,8 +79,8 @@ services:
       LOG_LEVEL: debug
       # ETH_NETWORK sets the network selected by Truffle from truffle-config.js
       # startup routines will wait for a blockchain client to be reachable on this network
-      ETH_NETWORK: blockchain1
-      BLOCKCHAIN_WS_HOST: blockchain1
+      ETH_NETWORK: blockchain
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       ZOKRATES_WORKER_HOST: worker
       USE_STUBS: 'false'
@@ -112,7 +112,7 @@ services:
       PROPOSER_HOST: proposer
       PROPOSER_PORT: 8080
       OPTIMIST_PORT: 80
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       CLIENT_HOST: client
       CLIENT_PORT: 80
@@ -130,7 +130,7 @@ services:
       OPTIMIST_PORT: 80
       CLIENT_HOST: client
       CLIENT_PORT: 80
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       IS_TEST_RUNNER: 'yes'
       PROPOSER_PORT: 8080
@@ -149,7 +149,7 @@ services:
       OPTIMIST_PORT: 80
       CLIENT_HOST: client
       CLIENT_PORT: 80
-      BLOCKCHAIN_WS_HOST: blockchain1
+      BLOCKCHAIN_WS_HOST: blockchain
       BLOCKCHAIN_PORT: 8546
       PROPOSER_PORT: 8080
       PROPOSER_HOST: proposer
diff --git a/test/rollback-resync.test.mjs b/test/rollback-resync.test.mjs
index c1c328262..87b971d93 100644
--- a/test/rollback-resync.test.mjs
+++ b/test/rollback-resync.test.mjs
@@ -180,7 +180,7 @@ describe('Running rollback and resync test', () => {
       );
 
       await sendTransactions(depositTransactions, [privateKey, shieldAddress, gas, fee]);
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
     });
 
     it('should make a block of transfers so we can make some bad blocks', async function () {
@@ -193,7 +193,7 @@ describe('Running rollback and resync test', () => {
       // eslint-disable-next-line prefer-destructuring
       duplicateTransaction = transferTransactions[0];
       await sendTransactions(transferTransactions, [privateKey, shieldAddress, gas, fee]);
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
     });
   });
 
@@ -219,7 +219,7 @@ describe('Running rollback and resync test', () => {
       validTransactions.push(...transferTransactions);
       await sendTransactions(transferTransactions, [privateKey, shieldAddress, gas, fee]);
 
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
     });
     it('should send the commit-challenge', async function () {
       while (!commitTxDataToSign) {
@@ -229,7 +229,7 @@ describe('Running rollback and resync test', () => {
       commitTxDataToSign = null;
     });
     it('Should delete the flawed block and rollback the leaves', async () => {
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['Rollback']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['Rollback']));
       await web3Client.testForEvents(stateAddress, [
         web3.eth.abi.encodeEventSignature('Rollback(bytes32,uint256,uint256)'),
         web3.eth.abi.encodeParameter('bytes32', topicsBlockHashDuplicateTransaction),
@@ -245,7 +245,7 @@ describe('Running rollback and resync test', () => {
         stdio: 'ignore',
       });
       resetOptimistDB.on('close', async () => {
-        spawn('docker', ['restart', 'nightfall_3_optimist1_1'], {
+        spawn('docker', ['restart', 'nightfall_3_optimist_1'], {
           stdio: 'ignore',
         });
 
@@ -330,7 +330,7 @@ describe('Running rollback and resync test', () => {
 
     it('should automatically create a bad block, as the resync will re-populate our local db', async () => {
       // This block will be a bad block as it uses the blockSubmissionFunction from the first bad block.
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
     });
 
     it('should make another good block on top of the bad block', async function () {
@@ -353,7 +353,7 @@ describe('Running rollback and resync test', () => {
       );
       await sendTransactions(depositTransactions, [privateKey, shieldAddress, gas, fee]);
       validTransactions.push(...depositTransactions);
-      eventLogs = await web3Client.waitForEvent(eventLogs, ['blockProposed']);
+      ({ eventLogs } = await web3Client.waitForEvent(eventLogs, ['blockProposed']));
     });
 
     it('should fire off the commit-challenge', async function () {
@@ -380,7 +380,7 @@ describe('Running rollback and resync test', () => {
         stdio: 'ignore',
       });
       resetOptimistDB.on('close', async () => {
-        spawn('docker', ['restart', 'nightfall_3_optimist1_1'], {
+        spawn('docker', ['restart', 'nightfall_3_optimist_1'], {
           stdio: 'ignore',
         });
         let healthCheck;
diff --git a/test/utils.mjs b/test/utils.mjs
index 4009679a1..5545d570b 100644
--- a/test/utils.mjs
+++ b/test/utils.mjs
@@ -66,16 +66,16 @@ export class Web3Client {
         for (const topic of log.topics) {
           switch (topic) {
             case topicEventMapping.BlockProposed:
-              queue.push('blockProposed');
+              queue.push({ eventName: 'blockProposed', log });
               break;
             case topicEventMapping.TransactionSubmitted:
-              queue.push('TransactionSubmitted');
+              queue.push({ eventName: 'TransactionSubmitted', log });
               break;
             case topicEventMapping.NewCurrentProposer:
-              queue.push('NewCurrentProposer');
+              queue.push({ eventName: 'NewCurrentProposer', log });
               break;
             default:
-              queue.push('Challenge');
+              queue.push({ eventName: 'Challenge', log });
               break;
           }
         }
@@ -142,7 +142,7 @@ export class Web3Client {
       receipt = await this.web3.eth.sendSignedTransaction(signed.rawTransaction);
       // the confirmations Promivent doesn't seem to terminate in Ganache, so we'll
       // just count 12 blocks before returning. TODO this won't handle a chain reorg.
-      console.log('waiting for twelve confirmations of transaction');
+      // console.log('waiting for twelve confirmations of transaction');
       const startBlock = await this.web3.eth.getBlock('latest');
       await new Promise(resolve => {
         const id = setInterval(async () => {
@@ -153,7 +153,7 @@ export class Web3Client {
           }
         }, 1000);
       });
-      console.log('transaction confirmed');
+      // console.log('transaction confirmed');
     } finally {
       this.isSubmitTxLocked = false;
     }
@@ -221,14 +221,14 @@ export class Web3Client {
       if (timeout === 0) throw new Error('Timeout in waitForEvent');
     }
 
-    while (eventLogs[0] !== expectedEvents[0]) {
+    while (eventLogs[0]?.eventName !== expectedEvents[0]) {
       await waitForTimeout(3000);
     }
 
-    expect(eventLogs[0]).to.equal(expectedEvents[0]);
-
+    expect(eventLogs[0].eventName).to.equal(expectedEvents[0]);
+    const eventsSeen = [];
     for (let i = 0; i < length; i++) {
-      eventLogs.shift();
+      eventsSeen.push(eventLogs.shift());
     }
 
     const blockHeaders = [];
@@ -241,7 +241,7 @@ export class Web3Client {
 
     // Have to wait here as client block proposal takes longer now
     await waitForTimeout(3000);
-    return eventLogs;
+    return { eventLogs, eventsSeen };
   }
 }
 
diff --git a/worker.Dockerfile b/worker.Dockerfile
index 3e17551ad..6eee39d26 100644
--- a/worker.Dockerfile
+++ b/worker.Dockerfile
@@ -29,4 +29,4 @@ COPY ./zokrates-worker/start-dev ./start-dev
 
 RUN npm ci
 
-CMD npm start
+CMD ["npm", "start"]