diff --git a/.eslintrc b/.eslintrc
new file mode 100644
index 0000000..ea565dd
--- /dev/null
+++ b/.eslintrc
@@ -0,0 +1,3 @@
+{
+  "extends": "ipfs"
+}
diff --git a/.github/workflows/typecheck.yml b/.github/workflows/typecheck.yml
new file mode 100644
index 0000000..624310c
--- /dev/null
+++ b/.github/workflows/typecheck.yml
@@ -0,0 +1,27 @@
+on:
+  push:
+    branches:
+      - master
+      - main
+      - default
+  pull_request:
+    branches:
+      - '**'
+
+name: Typecheck
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [12.x]
+    steps:
+      - uses: actions/checkout@v1
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install dependencies
+        run: npm install
+      - name: Typecheck
+        uses: gozala/typescript-error-reporter-action@v1.0.4
diff --git a/package.json b/package.json
index 7fd9020..148dd99 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,10 @@
   "main": "src/index.js",
   "scripts": {
     "lint": "aegir lint",
-    "build": "aegir build",
+    "check": "tsc --noEmit --noErrorTruncation",
+    "build": "npm run build:js && npm run build:types",
+    "build:js": "aegir build",
+    "build:types": "tsc --emitDeclarationOnly --declarationDir dist",
     "test": "aegir test",
     "test:node": "aegir test --target node",
     "test:browser": "aegir test --target browser",
@@ -15,7 +18,8 @@
     "release-major": "aegir release --type major --docs",
     "coverage": "aegir coverage",
     "coverage-publish": "aegir coverage --provider coveralls",
-    "docs": "aegir docs"
+    "docs": "aegir docs",
+    "prepare": "npm run build:types"
   },
   "pre-push": [
     "lint",
@@ -34,17 +38,24 @@
   },
   "homepage": "https://github.com/ipld/js-ipld-block#readme",
   "devDependencies": {
-    "aegir": "^25.0.0",
-    "uint8arrays": "^1.0.0"
+    "aegir": "^27.0.0",
+    "uint8arrays": "^1.0.0",
+    "typescript": "^4.0.3"
   },
   "dependencies": {
-    "cids": "^1.0.0",
-    "class-is": "^1.1.0"
+    "cids": "^1.0.0"
   },
   "engines": {
     "node": ">=6.0.0",
     "npm": ">=3.0.0"
   },
+  "typesVersions": {
+    "*": {
+      "*": [
+        "dist/*"
+      ]
+    }
+  },
   "contributors": [
     "David Dias <daviddias.p@gmail.com>",
     "Volker Mische <volker.mische@gmail.com>",
diff --git a/src/index.js b/src/index.js
index 07e1cbd..5d10c5c 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,7 +1,10 @@
 'use strict'
 
 const CID = require('cids')
-const withIs = require('class-is')
+
+const { version } = require('../package.json')
+const blockSymbol = Symbol.for('@ipld/js-ipld-block/block')
+const readonly = { writable: false, configurable: false, enumerable: true }
 
 /**
  * Represents an immutable block of data that is uniquely referenced with a cid.
@@ -9,9 +12,8 @@ const withIs = require('class-is')
  * @example
  * const block = new Block(Uint8Array.from([0, 1, 2, 3]), new CID('...'))
  */
-module.exports = class Block {
+class Block {
   /**
-   * @constructor
    * @param {Uint8Array} data - The data to be stored in the block as a Uint8Array.
    * @param {CID} cid - The cid of the data
    */
@@ -24,46 +26,77 @@ module.exports = class Block {
       throw new Error('second argument must be a CID')
     }
 
-    this._data = data
-    this._cid = cid
+    this.data = data
+    this.cid = cid
+
+    Object.defineProperties(this, {
+      data: readonly,
+      cid: readonly
+    })
   }
 
   /**
    * The data of this block.
    *
+   * @deprecated
    * @type {Uint8Array}
    */
-  get data () {
-    return this._data
-  }
-
-  set data (val) {
-    throw new Error('Tried to change an immutable block')
+  get _data () {
+    deprecateData()
+    return this.data
   }
 
   /**
    * The cid of the data this block represents.
    *
+   * @deprecated
    * @type {CID}
    */
-  get cid () {
-    return this._cid
+  get _cid () {
+    deprecateCID()
+    return this.cid
   }
 
-  set cid (val) {
-    throw new Error('Tried to change an immutable block')
+  get [Symbol.toStringTag] () {
+    return 'Block'
+  }
+
+  get [blockSymbol] () {
+    return true
   }
 
-  // eslint-disable-next-line valid-jsdoc
   /**
    * Check if the given value is a Block.
+   *
+   * @param {any} other
    * @returns {other is Block}
    */
-  static isBlock (other) { // eslint-disable-line no-unused-vars
-    // implemented by class-is module
+  static isBlock (other) {
+    return Boolean(other && other[blockSymbol])
   }
 }
 
-// to trick the typings engine
-// https://github.com/ipld/js-ipld-block/pull/55#discussion_r478845002
-module.exports = withIs(module.exports, { className: 'Block', symbolName: '@ipld/js-ipld-block/block' })
+/**
+ * @param {RegExp} range
+ * @param {string} message
+ * @returns {() => void}
+ */
+const deprecate = (range, message) => {
+  let warned = false
+  return () => {
+    if (range.test(version)) {
+      if (!warned) {
+        warned = true
+        // eslint-disable-next-line no-console
+        console.warn(message)
+      }
+    } else {
+      throw new Error(message)
+    }
+  }
+}
+
+const deprecateCID = deprecate(/^0\.10/, 'block._cid is deprecated and will be removed in the next major release. Use block.cid instead')
+const deprecateData = deprecate(/^0\.10/, 'block._data is deprecated and will be removed in the next major release. Use block.data instead')
+
+module.exports = Block
diff --git a/test/index.spec.js b/test/index.spec.js
index 15e0dee..dbdfd45 100644
--- a/test/index.spec.js
+++ b/test/index.spec.js
@@ -23,9 +23,18 @@ describe('block', () => {
   })
 
   it('create', () => {
-    const b = new Block(uint8ArrayFromString('hello'), new CID('QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n'))
+    const cid = new CID('QmdfTbBqBPQ7VNxZEYEj14VmRuZBkqFbiwReogJgS1zR1n')
+    const data = uint8ArrayFromString('hello')
+    const b = new Block(data, cid)
 
     expect(Block.isBlock(b)).to.eql(true)
+    expect(b.toString()).to.eql('[object Block]')
+    expect(b.data).to.eql(data)
+    expect(b.cid).to.eql(cid)
+    expect(b._data).to.eql(data)
+    expect(b._data).to.eql(data)
+    expect(b._cid).to.eql(cid)
+    expect(b._cid).to.eql(cid)
   })
 
   it('block stays immutable', () => {
@@ -34,13 +43,13 @@ describe('block', () => {
     expect(
       () => { b.data = 'fail' }
     ).to.throw(
-      /immutable/
+      /read.only/
     )
 
     expect(
       () => { b.cid = 'fail' }
     ).to.throw(
-      /immutable/
+      /read.only/
     )
   })
 })
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..4ce54b0
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,42 @@
+{
+  "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": "dist",
+    "skipLibCheck": true,
+    "stripInternal": true,
+    "resolveJsonModule": true,
+    "paths": {
+      "multiformats": [
+        "src"
+      ]
+    },
+    "baseUrl": "."
+  },
+  "include": [
+    "src"
+  ],
+  "exclude": [
+    "vendor",
+    "node_modules"
+  ],
+  "compileOnSave": false
+}