diff --git a/.aegir.js b/.aegir.cjs
similarity index 100%
rename from .aegir.js
rename to .aegir.cjs
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ef126da..0ca9e95 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -66,11 +66,13 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - run: npm install
-      - run: npx xvfb-maybe aegir test -t electron-main --bail
+      - run: npm run build -- --esm-tests # build tests with esm
+      - run: npx xvfb-maybe aegir test -t electron-main -f "dist/cjs/node-test/*js" --bail
   test-electron-renderer:
     needs: check
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - run: npm install
-      - run: npx xvfb-maybe aegir test -t electron-renderer --bail
+      - run: npm run build -- --esm-tests # build tests with esm
+      - run: npx xvfb-maybe aegir test -t electron-renderer -f "dist/cjs/node-test/*js" --bail
diff --git a/.gitignore b/.gitignore
index 8c93a42..5aa0b00 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 node_modules
 dist
+types
 docs
 package-lock.json
diff --git a/README.md b/README.md
index b329b9b..a922ff0 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ Compare two `Uint8Arrays`
 #### Example
 
 ```js
-const compare = require('uint8arrays/compare')
+import { compare } from 'uint8arrays/compare'
 
 const arrays = [
   Uint8Array.from([3, 4, 5]),
@@ -50,7 +50,7 @@ If you know the length of the arrays, pass it as a second parameter, otherwise i
 #### Example
 
 ```js
-const concat = require('uint8arrays/concat')
+import { concat } from 'uint8arrays/concat'
 
 const arrays = [
   Uint8Array.from([0, 1, 2]),
@@ -70,7 +70,7 @@ Returns true if the two arrays are the same array or if they have the same lengt
 #### Example
 
 ```js
-const equals = require('uint8arrays/equals')
+import { equals } from 'uint8arrays/equals'
 
 const a = Uint8Array.from([0, 1, 2])
 const b = Uint8Array.from([3, 4, 5])
@@ -90,7 +90,7 @@ Supports `utf8` and any of the [multibase encodings](https://github.com/multifor
 #### Example
 
 ```js
-const fromString = require('uint8arrays/from-string')
+import { fromString } from 'uint8arrays/from-string'
 
 console.info(fromString('hello world')) // Uint8Array[104, 101 ...
 console.info(fromString('00010203aabbcc', 'base16')) // Uint8Array[0, 1 ...
@@ -107,7 +107,7 @@ Supports `utf8` and any of the [multibase encodings](https://github.com/multifor
 #### Example
 
 ```js
-const toString = require('uint8arrays/to-string')
+import { toString } from 'uint8arrays/to-string'
 
 console.info(toString(Uint8Array.from([104, 101...]))) // 'hello world'
 console.info(toString(Uint8Array.from([0, 1, 2...]), 'base16')) // '00010203aabbcc'
@@ -122,7 +122,7 @@ Returns a `Uint8Array` containing `a` and `b` xored together.
 #### Example
 
 ```js
-const xor = require('uint8arrays/xor')
+import { xor } from 'uint8arrays/xor'
 
 console.info(xor(Uint8Array.from([1, 0]), Uint8Array.from([0, 1]))) // Uint8Array[1, 1]
 ```
diff --git a/index.js b/index.js
deleted file mode 100644
index f8ffa90..0000000
--- a/index.js
+++ /dev/null
@@ -1,16 +0,0 @@
-'use strict'
-const compare = require('./compare')
-const concat = require('./concat')
-const equals = require('./equals')
-const fromString = require('./from-string')
-const toString = require('./to-string')
-const xor = require('./xor')
-
-module.exports = {
-  compare,
-  concat,
-  equals,
-  fromString,
-  toString,
-  xor
-}
diff --git a/package.json b/package.json
index e7cb377..402e34d 100644
--- a/package.json
+++ b/package.json
@@ -2,40 +2,17 @@
   "name": "uint8arrays",
   "version": "2.1.8",
   "description": "Utility functions to make dealing with Uint8Arrays easier",
-  "main": "index.js",
+  "main": "src/index.js",
   "author": "Alex Potsides <alex@achingbrain.net>",
   "homepage": "https://github.com/achingbrain/uint8arrays",
   "bugs": "https://github.com/achingbrain/uint8arrays/issues",
-  "types": "dist/index.d.ts",
-  "typesVersions": {
-    "*": {
-      "*": [
-        "dist/*"
-      ],
-      "index.js": [
-        "dist/index.d.ts"
-      ]
-    }
-  },
-  "files": [
-    "compare.js",
-    "concat.js",
-    "equals.js",
-    "from-string.js",
-    "index.js",
-    "to-string.js",
-    "xor.js",
-    "dist/**/*.ts",
-    "dist/**/*.map",
-    "dist/**/*.js",
-    "util/*.js"
-  ],
+  "type": "module",
+  "types": "types/src/index.d.ts",
   "repository": {
     "type": "git",
     "url": "https://github.com/achingbrain/uint8arrays.git"
   },
   "scripts": {
-    "prepare": "aegir build --no-bundle",
     "test": "aegir test",
     "lint": "aegir ts -p check && aegir lint",
     "release": "aegir release",
@@ -48,15 +25,49 @@
     "multiformats": "^9.4.2"
   },
   "devDependencies": {
-    "aegir": "^34.0.2",
+    "aegir": "^35.0.0",
     "util": "^0.12.4"
   },
   "eslintConfig": {
     "extends": "ipfs",
+    "parserOptions": {
+      "sourceType": "module"
+    },
     "ignorePatterns": [
       "!.aegir.js"
     ]
   },
+  "typesVersions": {
+    "*": {
+      "*": [
+        "types/src",
+        "types/src/*"
+      ]
+    }
+  },
+  "exports": {
+    ".": {
+      "import": "./src/index.js"
+    },
+    "./compare": {
+      "import": "./src/compare.js"
+    },
+    "./concat": {
+      "import": "./src/concat.js"
+    },
+    "./equals": {
+      "import": "./src/equals.js"
+    },
+    "./from-string": {
+      "import": "./src/from-string.js"
+    },
+    "./to-string": {
+      "import": "./src/to-string.js"
+    },
+    "./xor": {
+      "import": "./src/xor.js"
+    }
+  },
   "contributors": [
     "achingbrain <alex@achingbrain.net>",
     "Cayman <caymannava@gmail.com>",
diff --git a/compare.js b/src/compare.js
similarity index 85%
rename from compare.js
rename to src/compare.js
index 951d4cb..d71d1f2 100644
--- a/compare.js
+++ b/src/compare.js
@@ -1,12 +1,10 @@
-'use strict'
-
 /**
  * Can be used with Array.sort to sort and array with Uint8Array entries
  *
  * @param {Uint8Array} a
  * @param {Uint8Array} b
  */
-function compare (a, b) {
+export function compare (a, b) {
   for (let i = 0; i < a.byteLength; i++) {
     if (a[i] < b[i]) {
       return -1
@@ -27,5 +25,3 @@ function compare (a, b) {
 
   return 0
 }
-
-module.exports = compare
diff --git a/concat.js b/src/concat.js
similarity index 84%
rename from concat.js
rename to src/concat.js
index c130089..e03970d 100644
--- a/concat.js
+++ b/src/concat.js
@@ -1,12 +1,10 @@
-'use strict'
-
 /**
  * Returns a new Uint8Array created by concatenating the passed ArrayLikes
  *
  * @param {Array<ArrayLike<number>>} arrays
  * @param {number} [length]
  */
-function concat (arrays, length) {
+export function concat (arrays, length) {
   if (!length) {
     length = arrays.reduce((acc, curr) => acc + curr.length, 0)
   }
@@ -21,5 +19,3 @@ function concat (arrays, length) {
 
   return output
 }
-
-module.exports = concat
diff --git a/equals.js b/src/equals.js
similarity index 84%
rename from equals.js
rename to src/equals.js
index af149f6..3d770b8 100644
--- a/equals.js
+++ b/src/equals.js
@@ -1,12 +1,10 @@
-'use strict'
-
 /**
  * Returns true if the two passed Uint8Arrays have the same content
  *
  * @param {Uint8Array} a
  * @param {Uint8Array} b
  */
-function equals (a, b) {
+export function equals (a, b) {
   if (a === b) {
     return true
   }
@@ -23,5 +21,3 @@ function equals (a, b) {
 
   return true
 }
-
-module.exports = equals
diff --git a/from-string.js b/src/from-string.js
similarity index 82%
rename from from-string.js
rename to src/from-string.js
index e869c7e..8f936d3 100644
--- a/from-string.js
+++ b/src/from-string.js
@@ -1,6 +1,4 @@
-'use strict'
-
-const bases = require('./util/bases')
+import bases from './util/bases.js'
 
 /**
  * @typedef {import('./util/bases').SupportedEncodings} SupportedEncodings
@@ -17,7 +15,7 @@ const bases = require('./util/bases')
  * @param {SupportedEncodings} [encoding=utf8] - utf8, base16, base64, base64urlpad, etc
  * @returns {Uint8Array}
  */
-function fromString (string, encoding = 'utf8') {
+export function fromString (string, encoding = 'utf8') {
   const base = bases[encoding]
 
   if (!base) {
@@ -27,5 +25,3 @@ function fromString (string, encoding = 'utf8') {
   // add multibase prefix
   return base.decoder.decode(`${base.prefix}${string}`)
 }
-
-module.exports = fromString
diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..411c9e0
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,15 @@
+import { compare } from './compare.js'
+import { concat } from './concat.js'
+import { equals } from './equals.js'
+import { fromString } from './from-string.js'
+import { toString } from './to-string.js'
+import { xor } from './xor.js'
+
+export {
+  compare,
+  concat,
+  equals,
+  fromString,
+  toString,
+  xor
+}
diff --git a/to-string.js b/src/to-string.js
similarity index 83%
rename from to-string.js
rename to src/to-string.js
index 670881c..c827584 100644
--- a/to-string.js
+++ b/src/to-string.js
@@ -1,6 +1,4 @@
-'use strict'
-
-const bases = require('./util/bases')
+import bases from './util/bases.js'
 
 /**
  * @typedef {import('./util/bases').SupportedEncodings} SupportedEncodings
@@ -17,7 +15,7 @@ const bases = require('./util/bases')
  * @param {SupportedEncodings} [encoding=utf8] - The encoding to use
  * @returns {string}
  */
-function toString (array, encoding = 'utf8') {
+export function toString (array, encoding = 'utf8') {
   const base = bases[encoding]
 
   if (!base) {
@@ -27,5 +25,3 @@ function toString (array, encoding = 'utf8') {
   // strip multibase prefix
   return base.encoder.encode(array).substring(1)
 }
-
-module.exports = toString
diff --git a/util/bases.js b/src/util/bases.js
similarity index 87%
rename from util/bases.js
rename to src/util/bases.js
index bc31fe1..79a0c18 100644
--- a/util/bases.js
+++ b/src/util/bases.js
@@ -1,6 +1,4 @@
-  'use strict'
-
-const { bases } = require('multiformats/basics')
+import { bases } from 'multiformats/basics'
 
 /**
  * @typedef {import('multiformats/bases/interface').MultibaseCodec<any>} MultibaseCodec
@@ -62,14 +60,14 @@ const ascii = createCodec('ascii', 'a', (buf) => {
  * @type {Record<SupportedEncodings, MultibaseCodec>}
  */
 const BASES = {
-  'utf8': string,
+  utf8: string,
   'utf-8': string,
-  'hex': bases.base16,
-  'latin1': ascii,
-  'ascii': ascii,
-  'binary': ascii,
+  hex: bases.base16,
+  latin1: ascii,
+  ascii: ascii,
+  binary: ascii,
 
   ...bases
 }
 
-module.exports = BASES
+export default BASES
diff --git a/xor.js b/src/xor.js
similarity index 85%
rename from xor.js
rename to src/xor.js
index dabbba9..35c014c 100644
--- a/xor.js
+++ b/src/xor.js
@@ -1,12 +1,10 @@
-'use strict'
-
 /**
  * Returns the xor distance between two arrays
  *
  * @param {Uint8Array} a
  * @param {Uint8Array} b
  */
-function xor (a, b) {
+export function xor (a, b) {
   if (a.length !== b.length) {
     throw new Error('Inputs should have the same length')
   }
@@ -19,5 +17,3 @@ function xor (a, b) {
 
   return result
 }
-
-module.exports = xor
diff --git a/test/compare.spec.js b/test/compare.spec.js
index f0c144c..7176fd7 100644
--- a/test/compare.spec.js
+++ b/test/compare.spec.js
@@ -1,8 +1,7 @@
 /* eslint-env mocha */
-'use strict'
 
-const { expect } = require('aegir/utils/chai')
-const compare = require('../compare')
+import { expect } from 'aegir/utils/chai.js'
+import { compare } from '../src/compare.js'
 
 describe('Uint8Array compare', () => {
   it('is stable', () => {
diff --git a/test/concat.spec.js b/test/concat.spec.js
index ecb6354..8156ac7 100644
--- a/test/concat.spec.js
+++ b/test/concat.spec.js
@@ -1,8 +1,7 @@
 /* eslint-env mocha */
-'use strict'
 
-const { expect } = require('aegir/utils/chai')
-const concat = require('../concat')
+import { expect } from 'aegir/utils/chai.js'
+import { concat } from '../src/concat.js'
 
 describe('Uint8Array concat', () => {
   it('concats two Uint8Arrays', () => {
diff --git a/test/equals.spec.js b/test/equals.spec.js
index 9129cf0..87efd87 100644
--- a/test/equals.spec.js
+++ b/test/equals.spec.js
@@ -1,8 +1,7 @@
 /* eslint-env mocha */
-'use strict'
 
-const { expect } = require('aegir/utils/chai')
-const equals = require('../equals')
+import { expect } from 'aegir/utils/chai.js'
+import { equals } from '../src/equals.js'
 
 describe('Uint8Array equals', () => {
   it('finds two Uint8Arrays equal', () => {
diff --git a/test/from-string.spec.js b/test/from-string.spec.js
index abc64ca..50bbab8 100644
--- a/test/from-string.spec.js
+++ b/test/from-string.spec.js
@@ -1,12 +1,11 @@
 /* eslint-env mocha */
-'use strict'
 
-const { expect } = require('aegir/utils/chai')
-const fromString = require('../from-string')
-const toString = require('../to-string')
-const bases = require('../util/bases')
+import { expect } from 'aegir/utils/chai.js'
+import { fromString } from '../src/from-string.js'
+import { toString } from '../src/to-string.js'
+import bases from '../src/util/bases.js'
 
-/** @type {import('../util/bases').SupportedEncodings[]} */
+/** @type {import('../src/util/bases').SupportedEncodings[]} */
 // @ts-ignore Object.keys returns a string[]
 const supportedBases = Object.keys(bases)
 
diff --git a/test/to-string.spec.js b/test/to-string.spec.js
index ca5a9c7..c610447 100644
--- a/test/to-string.spec.js
+++ b/test/to-string.spec.js
@@ -1,8 +1,7 @@
 /* eslint-env mocha */
-'use strict'
 
-const { expect } = require('aegir/utils/chai')
-const toString = require('../to-string')
+import { expect } from 'aegir/utils/chai.js'
+import { toString } from '../src/to-string.js'
 
 describe('Uint8Array toString', () => {
   it('creates a String from a Uint8Array', () => {
diff --git a/test/xor.spec.js b/test/xor.spec.js
index 3ceb306..81059ed 100644
--- a/test/xor.spec.js
+++ b/test/xor.spec.js
@@ -1,8 +1,7 @@
 /* eslint-env mocha */
-'use strict'
 
-const { expect } = require('aegir/utils/chai')
-const xor = require('../xor')
+import { expect } from 'aegir/utils/chai.js'
+import { xor } from '../src/xor.js'
 
 describe('Uint8Array xor', () => {
   it('xors 1,0 and 0,1', () => {
diff --git a/tsconfig.json b/tsconfig.json
index b0af813..ecde80b 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,12 +1,10 @@
 {
-    "extends": "aegir/src/config/tsconfig.aegir.json",
-    "compilerOptions": {
-        "outDir": "dist"
-    },
-    "include": [
-      "test",
-      "util",
-      "*.js",
-      ".aegir.js"
-    ]
+  "extends": "aegir/src/config/tsconfig.aegir.json",
+  "compilerOptions": {
+    "outDir": "./types"
+  },
+  "include": [
+    "src",
+    "test"
+  ]
 }