diff --git a/.github/workflows/mikeals-workflow.yml b/.github/workflows/mikeals-workflow.yml
index 1b88e24..d7787f0 100644
--- a/.github/workflows/mikeals-workflow.yml
+++ b/.github/workflows/mikeals-workflow.yml
@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [12.x, 14.x]
+        node-version: [12.x, 14.x, 16.x]
     steps:
     - uses: actions/checkout@v2
     - name: Use Node.js ${{ matrix.node-version }}
diff --git a/index.js b/index.js
index eca32ef..3efa1cd 100644
--- a/index.js
+++ b/index.js
@@ -1,57 +1,102 @@
 import json from 'fast-json-stable-stringify'
+// @ts-ignore
 import isCircular from '@ipld/is-circular'
 import transform from 'lodash.transform'
 import { bytes, CID } from 'multiformats'
 import { base64 } from 'multiformats/bases/base64'
 
-const _encode = (obj) => transform(obj, (result, value, key) => {
-  const cid = CID.asCID(value)
-  if (cid) {
-    result[key] = { '/': cid.toString() }
-  } else if (bytes.isBinary(value)) {
-    value = bytes.coerce(value)
-    result[key] = { '/': { bytes: base64.encode(value) } }
-  } else if (typeof value === 'object' && value !== null) {
-    result[key] = _encode(value)
-  } else {
-    result[key] = value
-  }
-})
+/**
+ * @template {number} Code
+ * @template T
+ * @typedef {import('multiformats/codecs/interface').BlockCodec<Code, T>} BlockCodec
+ */
+
+/**
+ * @template T
+ * @param {T} obj
+ * @returns {T}
+ */
+const transformEncode = (obj) => transform(obj,
+  /**
+   * @param {any} result
+   * @param {any} value
+   * @param {string} key
+   */
+  (result, value, key) => {
+    const cid = CID.asCID(value)
+    if (cid) {
+      result[key] = { '/': cid.toString() }
+    } else if (bytes.isBinary(value)) {
+      value = bytes.coerce(value)
+      result[key] = { '/': { bytes: base64.encode(value) } }
+    } else if (typeof value === 'object' && value !== null) {
+      result[key] = transformEncode(value)
+    } else {
+      result[key] = value
+    }
+  })
 
-const encode = (obj) => {
+/**
+ * @template T
+ * @param {T} obj
+ * @returns {Uint8Array}
+ */
+const _encode = (obj) => {
   if (typeof obj === 'object' && !bytes.isBinary(obj) && !CID.asCID(obj) && obj) {
     if (isCircular(obj, { asCID: true })) {
       throw new Error('Object contains circular references')
     }
-    obj = _encode(obj)
+    obj = transformEncode(obj)
   }
   return bytes.fromString(json(obj))
 }
 
-const _decode = (obj) => transform(obj, (result, value, key) => {
-  if (typeof value === 'object' && value !== null) {
-    if (value['/']) {
-      if (typeof value['/'] === 'string') {
-        result[key] = CID.parse(value['/'])
-      } else if (typeof value['/'] === 'object' && value['/'].bytes) {
-        result[key] = base64.decode(value['/'].bytes)
+/**
+ * @param {object} obj
+ * @returns {any}
+ */
+const transformDecode = (obj) => transform(obj,
+  /**
+   * @param {any} result
+   * @param {any} value
+   * @param {string} key
+   * @returns {any}
+   */
+  (result, value, key) => {
+    if (typeof value === 'object' && value !== null) {
+      if (value['/']) {
+        if (typeof value['/'] === 'string') {
+          result[key] = CID.parse(value['/'])
+        } else if (typeof value['/'] === 'object' && value['/'].bytes) {
+          result[key] = base64.decode(value['/'].bytes)
+        } else {
+          result[key] = transformDecode(value)
+        }
       } else {
-        result[key] = _decode(value)
+        result[key] = transformDecode(value)
       }
     } else {
-      result[key] = _decode(value)
+      result[key] = value
     }
-  } else {
-    result[key] = value
-  }
-})
+  })
 
-const decode = (buffer) => {
-  const obj = JSON.parse(bytes.toString(buffer))
-  return _decode({ value: obj }).value
+/**
+ * @template T
+ * @param {Uint8Array} data
+ * @returns {T}
+ */
+const _decode = (data) => {
+  const obj = JSON.parse(bytes.toString(data))
+  return transformDecode({ value: obj }).value
 }
 
-const name = 'dag-json'
-const code = 0x0129
-
-export { encode, decode, name, code }
+/**
+ * @template T
+ * @type {BlockCodec<0x0129, T>}
+ */
+export const { name, code, decode, encode } = {
+  name: 'dag-json',
+  code: 0x0129,
+  encode: _encode,
+  decode: _decode
+}
diff --git a/package.json b/package.json
index 5388c3f..c06ae2d 100644
--- a/package.json
+++ b/package.json
@@ -1,45 +1,67 @@
 {
   "name": "@ipld/dag-json",
   "version": "0.0.0-dev",
-  "description": "JSON Directed Acrylic Graph for IPLD",
+  "description": "JSON Directed Acrylic Graph (DAG-JSON) for IPLD",
+  "main": "index.js",
+  "types": "./types/index.d.ts",
   "type": "module",
-  "directories": {
-    "test": "test"
-  },
   "scripts": {
-    "lint": "standard",
-    "build": "npm_config_yes=true npx ipjs@latest build --tests",
-    "publish": "npm_config_yes=true npx ipjs@latest publish",
-    "test:cjs": "npm run build && mocha dist/cjs/node-test/test-*.js",
+    "lint": "standard *.js test/*.js",
+    "build": "npm run build:js && npm run build:types",
+    "build:js": "ipjs build --tests --main && npm run build:copy",
+    "build:copy": "cp -a tsconfig.json index.js dist/ && mkdir -p dist/test && cp test/*.js dist/test/",
+    "build:types": "npm run build:copy && cd dist && tsc --build",
+    "publish": "ipjs publish",
+    "test:cjs": "npm run build:js && mocha dist/cjs/node-test/test-*.js && npm run test:cjs:browser",
     "test:node": "hundreds mocha test/test-*.js",
-    "test:browser": "polendina --cleanup dist/cjs/node-test/test-*.js",
-    "test": "npm run lint && npm run test:node && npm run test:cjs && npm run test:browser",
-    "coverage": "c8 --reporter=html mocha test/test-*.js && npx st -d coverage -p 8080"
+    "test:cjs:browser": "polendina --page --worker --serviceworker --cleanup dist/cjs/node-test/test-*.js",
+    "test:ts": "npm run build:types && npm run test --prefix test/ts-use",
+    "test": "npm run lint && npm run test:node && npm run test:cjs && npm run test:ts",
+    "coverage": "c8 --reporter=html mocha test/test-*.js && npm_config_yes=true npx st -d coverage -p 8080"
   },
   "exports": {
     "import": "./index.js"
   },
+  "license": "(Apache-2.0 AND MIT)",
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/mikeal/dag-json.git"
+    "url": "git+https://github.com/ipld/js-dag-json.git"
   },
-  "keywords": [],
-  "author": "Mikeal Rogers <mikeal.rogers@gmail.com> (https://www.mikealrogers.com/)",
-  "license": "(Apache-2.0 AND MIT)",
+  "keywords": [
+    "IPFS",
+    "IPLD"
+  ],
   "bugs": {
-    "url": "https://github.com/mikeal/dag-json/issues"
-  },
-  "homepage": "https://github.com/mikeal/dag-json#readme",
-  "devDependencies": {
-    "hundreds": "0.0.8",
-    "mocha": "^8.1.1",
-    "polendina": "^1.1.0",
-    "standard": "^14.3.4"
+    "url": "https://github.com/ipld/js-dag-json/issues"
   },
+  "homepage": "https://github.com/ipld/js-dag-json",
   "dependencies": {
     "@ipld/is-circular": "^2.0.0",
+    "@types/lodash.transform": "^4.6.6",
     "fast-json-stable-stringify": "^2.1.0",
     "lodash.transform": "^4.6.0",
-    "multiformats": "^4.0.0"
-  }
+    "multiformats": "^7.0.0"
+  },
+  "devDependencies": {
+    "hundreds": "^0.0.9",
+    "ipjs": "^5.0.0",
+    "mocha": "^8.3.2",
+    "polendina": "^1.1.0",
+    "standard": "^16.0.3",
+    "typescript": "^4.2.4"
+  },
+  "directories": {
+    "test": "test"
+  },
+  "typesVersions": {
+    "*": {
+      "*": [
+        "types/*"
+      ],
+      "types/*": [
+        "types/*"
+      ]
+    }
+  },
+  "author": "Mikeal Rogers <mikeal.rogers@gmail.com> (https://www.mikealrogers.com/)"
 }
diff --git a/test/ts-use/.gitignore b/test/ts-use/.gitignore
new file mode 100644
index 0000000..6881777
--- /dev/null
+++ b/test/ts-use/.gitignore
@@ -0,0 +1,3 @@
+node_modules
+src/main.js
+tsconfig.tsbuildinfo
diff --git a/test/ts-use/package.json b/test/ts-use/package.json
new file mode 100644
index 0000000..70c5de1
--- /dev/null
+++ b/test/ts-use/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "ts-use",
+  "private": true,
+  "dependencies": {
+    "@ipld/dag-json": "file:../../dist/",
+    "multiformats": "file:../../node_modules/multiformats"
+  },
+  "scripts": {
+    "test": "npm install && npx -p typescript tsc && node src/main.js"
+  }
+}
diff --git a/test/ts-use/src/main.ts b/test/ts-use/src/main.ts
new file mode 100644
index 0000000..4ac245f
--- /dev/null
+++ b/test/ts-use/src/main.ts
@@ -0,0 +1,45 @@
+import { deepStrictEqual } from 'assert'
+
+import { BlockEncoder, BlockDecoder, BlockCodec } from 'multiformats/codecs/interface'
+import * as dagJson from '@ipld/dag-json'
+
+const main = () => {
+  // make sure we have a full CodecFeature
+  useCodecFeature(dagJson)
+}
+
+function useCodecFeature (codec: BlockCodec<297, any>) {
+  // use only as a BlockEncoder
+  useEncoder(codec)
+
+  // use only as a BlockDecoder
+  useDecoder(codec)
+
+  // use as a full BlockCodec which does both BlockEncoder & BlockDecoder
+  useBlockCodec(codec)
+}
+
+function useEncoder<Codec extends number> (encoder: BlockEncoder<Codec, string>) {
+  deepStrictEqual(encoder.code, 297)
+  deepStrictEqual(encoder.name, 'dag-json')
+  deepStrictEqual(Array.from(encoder.encode('blip')), [34, 98, 108, 105, 112, 34])
+  console.log('[TS] ✓ { encoder: BlockEncoder }')
+}
+
+function useDecoder<Codec extends number> (decoder: BlockDecoder<Codec, Uint8Array>) {
+  deepStrictEqual(decoder.code, 297)
+  deepStrictEqual(decoder.decode(Uint8Array.from([34, 98, 108, 105, 112, 34 ])), 'blip')
+  console.log('[TS] ✓ { decoder: BlockDecoder }')
+}
+
+function useBlockCodec<Codec extends number> (blockCodec: BlockCodec<Codec, string>) {
+  deepStrictEqual(blockCodec.code, 297)
+  deepStrictEqual(blockCodec.name, 'dag-json')
+  deepStrictEqual(Array.from(blockCodec.encode('blip')), [34, 98, 108, 105, 112, 34])
+  deepStrictEqual(blockCodec.decode(Uint8Array.from([34, 98, 108, 105, 112, 34])), 'blip')
+  console.log('[TS] ✓ {}:BlockCodec')
+}
+
+main()
+
+export default main
diff --git a/test/ts-use/tsconfig.json b/test/ts-use/tsconfig.json
new file mode 100644
index 0000000..ff14759
--- /dev/null
+++ b/test/ts-use/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "moduleResolution": "node",
+    "noImplicitAny": true,
+    "skipLibCheck": true,
+    "incremental": true
+  }
+}
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..58e8c8d
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,37 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "checkJs": true,
+    "forceConsistentCasingInFileNames": true,
+    "noImplicitReturns": false,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "strictFunctionTypes": false,
+    "strictNullChecks": true,
+    "strictPropertyInitialization": true,
+    "strictBindCallApply": true,
+    "strict": true,
+    "alwaysStrict": true,
+    "esModuleInterop": true,
+    "target": "ES2018",
+    "moduleResolution": "node",
+    "declaration": true,
+    "declarationMap": true,
+    "outDir": "types",
+    "skipLibCheck": true,
+    "stripInternal": true,
+    "resolveJsonModule": true,
+    "baseUrl": ".",
+    "emitDeclarationOnly": true
+  },
+  "include": [
+    "index.js"
+  ],
+  "exclude": [
+    "node_modules"
+  ],
+  "compileOnSave": false
+}