diff --git a/src/basics-browser.js b/src/basics-browser.js
index f4fef934..20e9afec 100644
--- a/src/basics-browser.js
+++ b/src/basics-browser.js
@@ -1,8 +1,8 @@
 // @ts-check
 
 import * as base64 from './bases/base64-browser.js'
-import { CID, hasher, digest, varint, bytes, hashes, codecs, bases as _bases } from './basics.js'
+import { CID, Block, hasher, digest, varint, bytes, hashes, codecs, bases as _bases } from './basics.js'
 
 const bases = { ..._bases, ...base64 }
 
-export { CID, hasher, digest, varint, bytes, hashes, codecs, bases }
+export { CID, Block, hasher, digest, varint, bytes, hashes, codecs, bases }
diff --git a/src/basics-import.js b/src/basics-import.js
index f5f2a224..2421269f 100644
--- a/src/basics-import.js
+++ b/src/basics-import.js
@@ -1,6 +1,6 @@
 
-import { CID, hasher, digest, varint, bytes, hashes, codecs, bases as _bases } from './basics.js'
+import { CID, Block, hasher, digest, varint, bytes, hashes, codecs, bases as _bases } from './basics.js'
 import * as base64 from './bases/base64-import.js'
 
 const bases = { ..._bases, ...base64 }
-export { CID, hasher, digest, varint, bytes, hashes, codecs, bases }
+export { CID, Block, hasher, digest, varint, bytes, hashes, codecs, bases }
diff --git a/src/basics.js b/src/basics.js
index 66974a19..37de1fe8 100644
--- a/src/basics.js
+++ b/src/basics.js
@@ -7,10 +7,10 @@ import * as sha2 from './hashes/sha2.js'
 import raw from './codecs/raw.js'
 import json from './codecs/json.js'
 
-import { CID, hasher, digest, varint, bytes } from './index.js'
+import { CID, Block, hasher, digest, varint, bytes } from './index.js'
 
 const bases = { ...base32, ...base58 }
 const hashes = { ...sha2 }
 const codecs = { raw, json }
 
-export { CID, hasher, digest, varint, bytes, hashes, bases, codecs }
+export { CID, Block, hasher, digest, varint, bytes, hashes, bases, codecs }
diff --git a/src/block.js b/src/block.js
new file mode 100644
index 00000000..3bed5724
--- /dev/null
+++ b/src/block.js
@@ -0,0 +1,308 @@
+// @ts-check
+
+import CID from './cid.js'
+
+/**
+ * @template {number} Code
+ * @template T
+ * @class
+ */
+export default class Block {
+  /**
+   * @param {CID|null} cid
+   * @param {Code} code
+   * @param {T} data
+   * @param {Uint8Array} bytes
+   * @param {BlockConfig} config
+   */
+  constructor (cid, code, data, bytes, { hasher }) {
+    /** @type {CID|Promise<CID>|null} */
+    this._cid = cid
+    this.code = code
+    this.data = data
+    this.bytes = bytes
+    this.hasher = hasher
+  }
+
+  async cid () {
+    const { _cid: cid } = this
+    if (cid != null) {
+      return await cid
+    } else {
+      const { bytes, code, hasher } = this
+      // First we store promise to avoid a race condition if cid is called
+      // whlie promise is pending.
+      const promise = createCID(hasher, bytes, code)
+      this._cid = promise
+      const cid = await promise
+      // Once promise resolves we store an actual CID.
+      this._cid = cid
+      return cid
+    }
+  }
+
+  links () {
+    return links(this.data, [])
+  }
+
+  tree () {
+    return tree(this.data, [])
+  }
+
+  /**
+   * @param {string} path
+   */
+  get (path) {
+    return get(this.data, path.split('/').filter(Boolean))
+  }
+
+  /**
+   * @template {number} Code
+   * @template T
+   * @param {Encoder<Code, T>} codec
+   * @param {BlockConfig} options
+   */
+  static encoder (codec, options) {
+    return new BlockEncoder(codec, options)
+  }
+
+  /**
+   * @template {number} Code
+   * @template T
+   * @param {Decoder<Code, T>} codec
+   * @param {BlockConfig} options
+   */
+  static decoder (codec, options) {
+    return new BlockDecoder(codec, options)
+  }
+
+  /**
+   * @template {number} Code
+   * @template T
+   * @param {Object} codec
+   * @param {Encoder<Code, T>} codec.encoder
+   * @param {Decoder<Code, T>} codec.decoder
+   * @param {BlockConfig} options
+   * @returns {BlockCodec<Code, T>}
+   */
+
+  static codec ({ encoder, decoder }, options) {
+    return new BlockCodec(encoder, decoder, options)
+  }
+}
+
+/**
+ * @template T
+ * @param {T} source
+ * @param {Array<string|number>} base
+ * @returns {Iterable<[string, CID]>}
+ */
+const links = function * (source, base) {
+  for (const [key, value] of Object.entries(source)) {
+    const path = [...base, key]
+    if (value != null && typeof value === 'object') {
+      if (Array.isArray(value)) {
+        for (const [index, element] of value.entries()) {
+          const elementPath = [...path, index]
+          const cid = CID.asCID(element)
+          if (cid) {
+            yield [elementPath.join('/'), cid]
+          } else if (typeof element === 'object') {
+            yield * links(element, elementPath)
+          }
+        }
+      } else {
+        const cid = CID.asCID(value)
+        if (cid) {
+          yield [path.join('/'), cid]
+        } else {
+          yield * links(value, path)
+        }
+      }
+    }
+  }
+}
+
+/**
+ * @template T
+ * @param {T} source
+ * @param {Array<string|number>} base
+ * @returns {Iterable<string>}
+ */
+const tree = function * (source, base) {
+  for (const [key, value] of Object.entries(source)) {
+    const path = [...base, key]
+    yield path.join('/')
+    if (value != null && typeof value === 'object' && !CID.asCID(value)) {
+      if (Array.isArray(value)) {
+        for (const [index, element] of value.entries()) {
+          const elementPath = [...path, index]
+          yield elementPath.join('/')
+          if (typeof element === 'object' && !CID.asCID(element)) {
+            yield * tree(element, elementPath)
+          }
+        }
+      } else {
+        yield * tree(value, path)
+      }
+    }
+  }
+}
+
+/**
+ * @template T
+ * @param {T} source
+ * @param {string[]} path
+ */
+const get = (source, path) => {
+  let node = source
+  for (const [index, key] of path.entries()) {
+    node = node[key]
+    if (node == null) {
+      throw new Error(`Object has no property at ${path.slice(0, index - 1).map(part => `[${JSON.stringify(part)}]`).join('')}`)
+    }
+    const cid = CID.asCID(node)
+    if (cid) {
+      return { value: cid, remaining: path.slice(index).join('/') }
+    }
+  }
+  return { value: node }
+}
+
+/**
+ *
+ * @param {Hasher} hasher
+ * @param {Uint8Array} bytes
+ * @param {number} code
+ */
+
+const createCID = async (hasher, bytes, code) => {
+  const multihash = await hasher.digest(bytes)
+  return CID.createV1(code, multihash)
+}
+
+/**
+ * @template {number} Code
+ * @template T
+ */
+class BlockCodec {
+  /**
+   * @param {Encoder<Code, T>} encoder
+   * @param {Decoder<Code, T>} decoder
+   * @param {BlockConfig} config
+   */
+
+  constructor (encoder, decoder, config) {
+    this.encoder = new BlockEncoder(encoder, config)
+    this.decoder = new BlockDecoder(decoder, config)
+    this.config = config
+  }
+
+  /**
+   * @param {Uint8Array} bytes
+   * @param {Partial<BlockConfig>} [options]
+   * @returns {Block<Code, T>}
+   */
+  decode (bytes, options) {
+    return this.decoder.decode(bytes, { ...this.config, ...options })
+  }
+
+  /**
+   * @param {T} data
+   * @param {Partial<BlockConfig>} [options]
+   * @returns {Block<Code, T>}
+   */
+  encode (data, options) {
+    return this.encoder.encode(data, { ...this.config, ...options })
+  }
+}
+
+/**
+ * @class
+ * @template {number} Code
+ * @template T
+ */
+class BlockEncoder {
+  /**
+   * @param {Encoder<Code, T>} codec
+   * @param {BlockConfig} config
+   */
+  constructor (codec, config) {
+    this.codec = codec
+    this.config = config
+  }
+
+  /**
+   * @param {T} data
+   * @param {Partial<BlockConfig>} [options]
+   * @returns {Block<Code, T>}
+   */
+  encode (data, options) {
+    const { codec } = this
+    const bytes = codec.encode(data)
+    return new Block(null, codec.code, data, bytes, { ...this.config, ...options })
+  }
+}
+
+/**
+ * @class
+ * @template {number} Code
+ * @template T
+ */
+class BlockDecoder {
+  /**
+   * @param {Decoder<Code, T>} codec
+   * @param {BlockConfig} config
+   */
+  constructor (codec, config) {
+    this.codec = codec
+    this.config = config
+  }
+
+  /**
+   * @param {Uint8Array} bytes
+   * @param {Partial<BlockConfig>} [options]
+   * @returns {Block<Code, T>}
+   */
+  decode (bytes, options) {
+    const data = this.codec.decode(bytes)
+    return new Block(null, this.codec.code, data, bytes, { ...this.config, ...options })
+  }
+}
+/**
+ * @typedef {import('./block/interface').Config} BlockConfig
+ * @typedef {import('./hashes/interface').MultihashHasher} Hasher
+ **/
+
+/**
+ * @template T
+ * @typedef {import('./bases/interface').MultibaseEncoder<T>} MultibaseEncoder
+ */
+
+/**
+ * @template T
+ * @typedef {import('./bases/interface').MultibaseDecoder<T>} MultibaseDecoder
+ */
+
+/**
+ * @template T
+ * @typedef {import('./bases/interface').MultibaseCodec<T>} MultibaseCodec
+ */
+
+/**
+ * @template {number} Code
+ * @template T
+ * @typedef {import('./codecs/interface').BlockEncoder<Code, T>} Encoder
+ */
+
+/**
+ * @template {number} Code
+ * @template T
+ * @typedef {import('./codecs/interface').BlockDecoder<Code, T>} Decoder
+ */
+
+/**
+ * @template {number} Code
+ * @template T
+ * @typedef {import('./codecs/interface').BlockCodec<Code, T>} Codec
+ */
diff --git a/src/index.js b/src/index.js
index d3d3144e..3ce64497 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,10 +1,11 @@
 // @ts-check
 
 import CID from './cid.js'
+import Block from './block.js'
 import * as varint from './varint.js'
 import * as bytes from './bytes.js'
 import * as hasher from './hashes/hasher.js'
 import * as digest from './hashes/digest.js'
 import * as codec from './codecs/codec.js'
 
-export { CID, hasher, digest, varint, bytes, codec }
+export { CID, Block, hasher, digest, varint, bytes, codec }