diff --git a/src/block.ts b/src/block.ts
index ae59ff13..3e2f9504 100644
--- a/src/block.ts
+++ b/src/block.ts
@@ -141,7 +141,7 @@ export async function encode <T, Code extends number, Alg extends number> ({ val
   if (typeof value === 'undefined') throw new Error('Missing required argument "value"')
   if (codec == null || hasher == null) throw new Error('Missing required argument: codec or hasher')
 
-  const bytes = codec.encode(value)
+  const bytes = await Promise.resolve(codec.encode(value))
   const hash = await hasher.digest(bytes)
   // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
   const cid = CID.create(
@@ -168,7 +168,7 @@ export async function decode <T, Code extends number, Alg extends number> ({ byt
   if (bytes == null) throw new Error('Missing required argument "bytes"')
   if (codec == null || hasher == null) throw new Error('Missing required argument: codec or hasher')
 
-  const value = codec.decode(bytes)
+  const value = await Promise.resolve(codec.decode(bytes))
   const hash = await hasher.digest(bytes)
   // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
   const cid = CID.create(1, codec.code, hash) as CID<T, Code, Alg, 1>
@@ -194,10 +194,10 @@ type CreateUnsafeInput <T, Code extends number, Alg extends number, V extends AP
  * @template Alg - multicodec code corresponding to the hashing algorithm used in CID creation.
  * @template V - CID version
  */
-export function createUnsafe <T, Code extends number, Alg extends number, V extends API.Version> ({ bytes, cid, value: maybeValue, codec }: CreateUnsafeInput<T, Code, Alg, V>): API.BlockView<T, Code, Alg, V> {
-  const value = maybeValue !== undefined
+export async function createUnsafe <T, Code extends number, Alg extends number, V extends API.Version> ({ bytes, cid, value: maybeValue, codec }: CreateUnsafeInput<T, Code, Alg, V>): Promise<API.BlockView<T, Code, Alg, V>> {
+  const value = await Promise.resolve(maybeValue !== undefined
     ? maybeValue
-    : (codec?.decode(bytes))
+    : (codec?.decode(bytes)))
 
   if (value === undefined) throw new Error('Missing required argument, must either provide "value" or "codec"')
 
@@ -224,7 +224,7 @@ interface CreateInput <T, Code extends number, Alg extends number, V extends API
 export async function create <T, Code extends number, Alg extends number, V extends API.Version> ({ bytes, cid, hasher, codec }: CreateInput<T, Code, Alg, V>): Promise<API.BlockView<T, Code, Alg, V>> {
   if (bytes == null) throw new Error('Missing required argument "bytes"')
   if (hasher == null) throw new Error('Missing required argument "hasher"')
-  const value = codec.decode(bytes)
+  const value = await Promise.resolve(codec.decode(bytes))
   const hash = await hasher.digest(bytes)
   if (!binary.equals(cid.multihash.bytes, hash.bytes)) {
     throw new Error('CID hash does not match bytes')
diff --git a/src/codecs/interface.ts b/src/codecs/interface.ts
index 8e5d9d1a..61b5394e 100644
--- a/src/codecs/interface.ts
+++ b/src/codecs/interface.ts
@@ -6,7 +6,7 @@ import type { ArrayBufferView, ByteView } from '../block/interface.js'
 export interface BlockEncoder<Code extends number, T> {
   name: string
   code: Code
-  encode(data: T): ByteView<T>
+  encode(data: T): ByteView<T> | PromiseLike<ByteView<T>>
 }
 
 /**
@@ -14,7 +14,7 @@ export interface BlockEncoder<Code extends number, T> {
  */
 export interface BlockDecoder<Code extends number, T> {
   code: Code
-  decode(bytes: ByteView<T> | ArrayBufferView<T>): T
+  decode(bytes: ByteView<T> | ArrayBufferView<T>): T | PromiseLike<T>
 }
 
 /**
diff --git a/test/test-block.spec.ts b/test/test-block.spec.ts
index 120be93c..30c07e8e 100644
--- a/test/test-block.spec.ts
+++ b/test/test-block.spec.ts
@@ -10,6 +10,20 @@ const fixture = { hello: 'world' }
 const link = CID.parse('bafyreidykglsfhoixmivffc5uwhcgshx4j465xwqntbmu43nb2dzqwfvae')
 const buff = bytes.fromString('sadf')
 
+describe('promise-resolve-semantics', () => {
+  it('should resolve to the value', async () => {
+    const value = await Promise.resolve('hello')
+    assert.equal(value, 'hello')
+  })
+  it('should resolve to the promise value', async () => {
+    // eslint-disable-next-line promise/param-names
+    const value = await Promise.resolve(new Promise<string>(function (rs: (value: string) => void) {
+      setTimeout(function () { rs('hello') }, 10)
+    }))
+    assert.equal(value, 'hello')
+  })
+})
+
 describe('block', () => {
   it('basic encode/decode roundtrip', async () => {
     const block = await main.encode({ value: fixture, codec, hasher })
@@ -23,7 +37,7 @@ describe('block', () => {
 
   it('createUnsafe', async () => {
     const block = await main.encode({ value: fixture, codec, hasher })
-    const block2 = main.createUnsafe({ bytes: block.bytes, cid: block.cid, codec })
+    const block2 = await main.createUnsafe({ bytes: block.bytes, cid: block.cid, codec })
     assert.deepStrictEqual(block.cid.equals(block2.cid), true)
   })
 
@@ -36,25 +50,29 @@ describe('block', () => {
       // @ts-expect-error - 'string' is not assignable to parameter of type 'ArrayLike<number>'
       bytes: Uint8Array.from('1234')
     }
-    // @ts-expect-error - 'boolean' is not assignable to type 'CID'
-    const block = main.createUnsafe({ value, codec, hasher, cid: true, bytes: true })
 
-    it('links', () => {
+    it('links', async () => {
       const expected = ['link', 'arr/0']
+      // @ts-expect-error - 'boolean' is not assignable to type 'CID'
+      const block = await main.createUnsafe({ value, codec, hasher, cid: true, bytes: true })
       for (const [path, cid] of block.links()) {
         assert.deepStrictEqual(path, expected.shift())
         assert.deepStrictEqual(cid.toString(), link.toString())
       }
     })
 
-    it('tree', () => {
+    it('tree', async () => {
       const expected = ['link', 'nope', 'arr', 'arr/0', 'obj', 'obj/arr', 'obj/arr/0', 'obj/arr/0/obj', 'bytes']
+      // @ts-expect-error - 'boolean' is not assignable to type 'CID'
+      const block = await main.createUnsafe({ value, codec, hasher, cid: true, bytes: true })
       for (const path of block.tree()) {
         assert.deepStrictEqual(path, expected.shift())
       }
     })
 
-    it('get', () => {
+    it('get', async () => {
+      // @ts-expect-error - 'boolean' is not assignable to type 'CID'
+      const block = await main.createUnsafe({ value, codec, hasher, cid: true, bytes: true })
       let ret = block.get('link/test')
       assert.deepStrictEqual(ret.remaining, 'test')
       assert.deepStrictEqual(String(ret.value), link.toString())
@@ -63,8 +81,8 @@ describe('block', () => {
       assert.deepStrictEqual(ret, { value: 'skip' })
     })
 
-    it('null links/tree', () => {
-      const block = main.createUnsafe({
+    it('null links/tree', async () => {
+      const block = await main.createUnsafe({
         value: null,
         codec,
         hasher,
@@ -95,9 +113,9 @@ describe('block', () => {
     assert.equal(links[0][1].toString(), link.toString())
   })
 
-  it('kitchen sink', () => {
+  it('kitchen sink', async () => {
     const sink = { one: { two: { arr: [true, false, null], three: 3, buff, link } } }
-    const block = main.createUnsafe({
+    const block = await main.createUnsafe({
       value: sink,
       codec,
       // @ts-expect-error - 'boolean' is not assignable to type 'ByteView<unknown>'
@@ -132,8 +150,13 @@ describe('block', () => {
     })
 
     it('createUnsafe', async () => {
-      // @ts-expect-error testing invalid usage
-      assert.throws(() => main.createUnsafe({}), 'Missing required argument, must either provide "value" or "codec"')
+      try {
+        // @ts-expect-error testing invalid usage
+        await main.createUnsafe({})
+        assert(false, 'Missing required argument, must either provide "value" or "codec"')
+      } catch (/** @type {Error} */ err) {
+        /* c8 ignore next */
+      }
     })
 
     it('create', async () => {
diff --git a/test/test-multibase-spec.spec.ts b/test/test-multibase-spec.spec.ts
index 1f7f2523..db5dbece 100644
--- a/test/test-multibase-spec.spec.ts
+++ b/test/test-multibase-spec.spec.ts
@@ -174,9 +174,11 @@ describe('spec test', () => {
   }
 
   for (const base of Object.values(bases)) {
-    it('should fail decode with invalid char', function () {
+    // eslint-disable-next-line @typescript-eslint/method-signature-style
+    it('should fail decode with invalid char', function (this: { skip: () => void }) {
       if (base.name === 'identity') {
-        return this.skip()
+        this.skip()
+        return
       }
 
       assert.throws(() => base.decode(base.prefix + '^!@$%!#$%@#y'), `Non-${base.name} character`)