diff --git a/src/common.ts b/src/common.ts
index 81d4fba6..7caa6d2b 100644
--- a/src/common.ts
+++ b/src/common.ts
@@ -14,6 +14,8 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+import { ArconnectSigner, ArweaveSigner } from 'arbundles';
+
 import {
   ANTRecord,
   ANTState,
@@ -32,13 +34,17 @@ export type SortKey = string;
 export type WalletAddress = string;
 
 // TODO: append this with other configuration options (e.g. local vs. remote evaluation)
-export type ContractConfiguration =
-  | {
+export type ArIOSigner = ArweaveSigner | ArconnectSigner;
+export type ContractConfiguration = {
+  signer?: ArIOSigner; // TODO: optionally allow JWK in place of signer
+} & (
+    | {
       contract?: SmartWeaveContract<unknown>;
     }
-  | {
+    | {
       contractTxId: string;
-    };
+    }
+  );
 
 export function isContractConfiguration<T>(
   config: ContractConfiguration,
diff --git a/src/common/ant.ts b/src/common/ant.ts
index dd3f705e..d5de3259 100644
--- a/src/common/ant.ts
+++ b/src/common/ant.ts
@@ -29,8 +29,12 @@ import { RemoteContract } from './contracts/remote-contract.js';
 
 export class ANT implements ANTContract {
   private contract: SmartWeaveContract<ANTState>;
+  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+  // @ts-ignore
+  private signer: ArIOSigner | undefined;
 
-  constructor(config: ContractConfiguration) {
+  constructor({ signer, ...config }: ContractConfiguration) {
+    this.signer = signer;
     if (isContractConfiguration<ANTState>(config)) {
       this.contract = config.contract;
     } else if (isContractTxIdConfiguration(config)) {
diff --git a/src/common/ar-io.ts b/src/common/ar-io.ts
index 0b783fbe..fa25e62f 100644
--- a/src/common/ar-io.ts
+++ b/src/common/ar-io.ts
@@ -14,8 +14,7 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-import { ArconnectSigner, ArweaveSigner } from 'arbundles';
-
+import { ARNS_TESTNET_REGISTRY_TX } from '../constants.js';
 import {
   ArIOContract,
   ArIOState,
@@ -33,19 +32,6 @@ import {
 } from '../types.js';
 import { RemoteContract } from './contracts/remote-contract.js';
 
-// TODO: append this with other configuration options (e.g. local vs. remote evaluation)
-export type ArIOSigner = ArweaveSigner | ArconnectSigner;
-export type ContractConfiguration = {
-  signer?: ArIOSigner; // TODO: optionally allow JWK in place of signer
-} & (
-  | {
-      contract?: SmartWeaveContract<unknown>;
-    }
-  | {
-      contractTxId: string;
-    }
-);
-
 function isContractConfiguration<T>(
   config: ContractConfiguration,
 ): config is { contract: SmartWeaveContract<T> } {
@@ -64,7 +50,13 @@ export class ArIO implements ArIOContract {
   // @ts-ignore
   private signer: ArIOSigner | undefined;
 
-  constructor({ signer, ...config }: ContractConfiguration) {
+  constructor(
+    { signer, ...config }: ContractConfiguration = {
+      contract: new RemoteContract<ArIOState>({
+        contractTxId: ARNS_TESTNET_REGISTRY_TX,
+      }),
+    },
+  ) {
     this.signer = signer;
     if (isContractConfiguration<ArIOState>(config)) {
       this.contract = config.contract;