diff --git a/crates/backend/src/typegen.rs b/crates/backend/src/typegen.rs
index 1299f621..75c4ccbd 100644
--- a/crates/backend/src/typegen.rs
+++ b/crates/backend/src/typegen.rs
@@ -410,6 +410,13 @@ pub fn ty_to_ts_type(
               Some((rust_ty, false))
             }
           });
+        } else if rust_ty == "AsyncBlock" {
+          if let Some(arg) = args.first() {
+            ts_ty = Some((format!("Promise<{}>", arg.0), false));
+          } else {
+            // Not NAPI-RS `AsyncBlock`
+            ts_ty = Some((rust_ty, false));
+          }
         } else if let Some(&(known_ty, _, _)) = KNOWN_TYPES.get(rust_ty.as_str()) {
           if rust_ty == "()" && is_return_ty {
             ts_ty = Some(("void".to_owned(), false));
diff --git a/crates/napi/src/bindgen_runtime/js_values/buffer.rs b/crates/napi/src/bindgen_runtime/js_values/buffer.rs
index 7ff433d0..c24b0aa4 100644
--- a/crates/napi/src/bindgen_runtime/js_values/buffer.rs
+++ b/crates/napi/src/bindgen_runtime/js_values/buffer.rs
@@ -347,6 +347,7 @@ impl Drop for Buffer {
 /// SAFETY: This is undefined behavior, as the JS side may always modify the underlying buffer,
 /// without synchronization. Also see the docs for the `AsMut` impl.
 unsafe impl Send for Buffer {}
+unsafe impl Sync for Buffer {}
 
 impl Clone for Buffer {
   fn clone(&self) -> Self {
diff --git a/crates/napi/src/tokio_runtime.rs b/crates/napi/src/tokio_runtime.rs
index 6e77678f..bdd3a333 100644
--- a/crates/napi/src/tokio_runtime.rs
+++ b/crates/napi/src/tokio_runtime.rs
@@ -6,7 +6,9 @@ use std::{
 
 use tokio::runtime::Runtime;
 
-use crate::{sys, Error, JsDeferred, JsUnknown, NapiValue, Result};
+use crate::{
+  bindgen_runtime::ToNapiValue, sys, Env, Error, JsDeferred, JsUnknown, NapiValue, Result,
+};
 
 fn create_runtime() -> Option<Runtime> {
   #[cfg(not(target_family = "wasm"))]
@@ -221,3 +223,55 @@ pub fn execute_tokio_future<
 
   Ok(promise.0.value)
 }
+
+pub struct AsyncBlockBuilder<
+  V: ToNapiValue + Send + 'static,
+  F: Future<Output = Result<V>> + Send + 'static,
+  Dispose: FnOnce(Env) + 'static,
+> {
+  inner: F,
+  dispose: Option<Dispose>,
+}
+
+impl<
+    V: ToNapiValue + Send + 'static,
+    F: Future<Output = Result<V>> + Send + 'static,
+    Dispose: FnOnce(Env),
+  > AsyncBlockBuilder<V, F, Dispose>
+{
+  pub fn with(inner: F) -> Self {
+    Self {
+      inner,
+      dispose: None,
+    }
+  }
+
+  pub fn with_dispose(mut self, dispose: Dispose) -> Self {
+    self.dispose = Some(dispose);
+    self
+  }
+
+  pub fn build(self, env: Env) -> Result<AsyncBlock<V>> {
+    Ok(AsyncBlock {
+      inner: execute_tokio_future(env.0, self.inner, |env, v| unsafe {
+        if let Some(dispose) = self.dispose {
+          let env = Env::from_raw(env);
+          dispose(env);
+        }
+        V::to_napi_value(env, v)
+      })?,
+      _phantom: PhantomData,
+    })
+  }
+}
+
+pub struct AsyncBlock<T: ToNapiValue + Send + 'static> {
+  inner: sys::napi_value,
+  _phantom: PhantomData<T>,
+}
+
+impl<T: ToNapiValue + Send + 'static> ToNapiValue for AsyncBlock<T> {
+  unsafe fn to_napi_value(_: napi_sys::napi_env, val: Self) -> Result<napi_sys::napi_value> {
+    Ok(val.inner)
+  }
+}
diff --git a/examples/napi/__tests__/__snapshots__/typegen.spec.ts.md b/examples/napi/__tests__/__snapshots__/typegen.spec.ts.md
index 833cce80..0fab6a4c 100644
--- a/examples/napi/__tests__/__snapshots__/typegen.spec.ts.md
+++ b/examples/napi/__tests__/__snapshots__/typegen.spec.ts.md
@@ -335,6 +335,8 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export declare function bufferPassThrough(buf: Buffer): Promise<Buffer>␊
     ␊
+    export declare function bufferWithAsyncBlock(buf: Buffer): Promise<number>␊
+    ␊
     export declare function buildThreadsafeFunctionFromFunction(callback: (arg0: number, arg1: number) => number): void␊
     ␊
     export declare function buildThreadsafeFunctionFromFunctionCalleeHandle(callback: () => void): void␊
diff --git a/examples/napi/__tests__/__snapshots__/typegen.spec.ts.snap b/examples/napi/__tests__/__snapshots__/typegen.spec.ts.snap
index 3a3c8203..b4856e1d 100644
Binary files a/examples/napi/__tests__/__snapshots__/typegen.spec.ts.snap and b/examples/napi/__tests__/__snapshots__/typegen.spec.ts.snap differ
diff --git a/examples/napi/example.wasi-browser.js b/examples/napi/example.wasi-browser.js
index 55b5efba..7077cc4d 100644
--- a/examples/napi/example.wasi-browser.js
+++ b/examples/napi/example.wasi-browser.js
@@ -359,29 +359,30 @@ function __napi_rs_initialize_modules(__napiInstance) {
   __napiInstance.exports['__napi_register__mutate_typed_array_363']?.()
   __napiInstance.exports['__napi_register__deref_uint8_array_364']?.()
   __napiInstance.exports['__napi_register__buffer_pass_through_365']?.()
-  __napiInstance.exports['__napi_register__array_buffer_pass_through_366']?.()
-  __napiInstance.exports['__napi_register__accept_slice_367']?.()
-  __napiInstance.exports['__napi_register__accept_arraybuffer_368']?.()
-  __napiInstance.exports['__napi_register__create_arraybuffer_369']?.()
-  __napiInstance.exports['__napi_register__u8_array_to_array_370']?.()
-  __napiInstance.exports['__napi_register__i8_array_to_array_371']?.()
-  __napiInstance.exports['__napi_register__u16_array_to_array_372']?.()
-  __napiInstance.exports['__napi_register__i16_array_to_array_373']?.()
-  __napiInstance.exports['__napi_register__u32_array_to_array_374']?.()
-  __napiInstance.exports['__napi_register__i32_array_to_array_375']?.()
-  __napiInstance.exports['__napi_register__f32_array_to_array_376']?.()
-  __napiInstance.exports['__napi_register__f64_array_to_array_377']?.()
-  __napiInstance.exports['__napi_register__u64_array_to_array_378']?.()
-  __napiInstance.exports['__napi_register__i64_array_to_array_379']?.()
-  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_380']?.()
-  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_and_buffer_slice_381']?.()
-  __napiInstance.exports['__napi_register__AsyncBuffer_impl_382']?.()
-  __napiInstance.exports['__napi_register__async_reduce_buffer_383']?.()
-  __napiInstance.exports['__napi_register__async_buffer_to_array_384']?.()
-  __napiInstance.exports['__napi_register__u_init8_array_from_string_385']?.()
-  __napiInstance.exports['__napi_register__AsyncReader_impl_386']?.()
-  __napiInstance.exports['__napi_register__Reader_struct_387']?.()
-  __napiInstance.exports['__napi_register__Reader_impl_389']?.()
+  __napiInstance.exports['__napi_register__buffer_with_async_block_366']?.()
+  __napiInstance.exports['__napi_register__array_buffer_pass_through_367']?.()
+  __napiInstance.exports['__napi_register__accept_slice_368']?.()
+  __napiInstance.exports['__napi_register__accept_arraybuffer_369']?.()
+  __napiInstance.exports['__napi_register__create_arraybuffer_370']?.()
+  __napiInstance.exports['__napi_register__u8_array_to_array_371']?.()
+  __napiInstance.exports['__napi_register__i8_array_to_array_372']?.()
+  __napiInstance.exports['__napi_register__u16_array_to_array_373']?.()
+  __napiInstance.exports['__napi_register__i16_array_to_array_374']?.()
+  __napiInstance.exports['__napi_register__u32_array_to_array_375']?.()
+  __napiInstance.exports['__napi_register__i32_array_to_array_376']?.()
+  __napiInstance.exports['__napi_register__f32_array_to_array_377']?.()
+  __napiInstance.exports['__napi_register__f64_array_to_array_378']?.()
+  __napiInstance.exports['__napi_register__u64_array_to_array_379']?.()
+  __napiInstance.exports['__napi_register__i64_array_to_array_380']?.()
+  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_381']?.()
+  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_and_buffer_slice_382']?.()
+  __napiInstance.exports['__napi_register__AsyncBuffer_impl_383']?.()
+  __napiInstance.exports['__napi_register__async_reduce_buffer_384']?.()
+  __napiInstance.exports['__napi_register__async_buffer_to_array_385']?.()
+  __napiInstance.exports['__napi_register__u_init8_array_from_string_386']?.()
+  __napiInstance.exports['__napi_register__AsyncReader_impl_387']?.()
+  __napiInstance.exports['__napi_register__Reader_struct_388']?.()
+  __napiInstance.exports['__napi_register__Reader_impl_390']?.()
 }
 export const Animal = __napiModule.exports.Animal
 export const AnimalWithDefaultConstructor = __napiModule.exports.AnimalWithDefaultConstructor
@@ -453,6 +454,7 @@ export const bigintGetU64AsString = __napiModule.exports.bigintGetU64AsString
 export const btreeSetToJs = __napiModule.exports.btreeSetToJs
 export const btreeSetToRust = __napiModule.exports.btreeSetToRust
 export const bufferPassThrough = __napiModule.exports.bufferPassThrough
+export const bufferWithAsyncBlock = __napiModule.exports.bufferWithAsyncBlock
 export const buildThreadsafeFunctionFromFunction = __napiModule.exports.buildThreadsafeFunctionFromFunction
 export const buildThreadsafeFunctionFromFunctionCalleeHandle = __napiModule.exports.buildThreadsafeFunctionFromFunctionCalleeHandle
 export const call0 = __napiModule.exports.call0
diff --git a/examples/napi/example.wasi.cjs b/examples/napi/example.wasi.cjs
index eabcb25a..e132e565 100644
--- a/examples/napi/example.wasi.cjs
+++ b/examples/napi/example.wasi.cjs
@@ -383,29 +383,30 @@ function __napi_rs_initialize_modules(__napiInstance) {
   __napiInstance.exports['__napi_register__mutate_typed_array_363']?.()
   __napiInstance.exports['__napi_register__deref_uint8_array_364']?.()
   __napiInstance.exports['__napi_register__buffer_pass_through_365']?.()
-  __napiInstance.exports['__napi_register__array_buffer_pass_through_366']?.()
-  __napiInstance.exports['__napi_register__accept_slice_367']?.()
-  __napiInstance.exports['__napi_register__accept_arraybuffer_368']?.()
-  __napiInstance.exports['__napi_register__create_arraybuffer_369']?.()
-  __napiInstance.exports['__napi_register__u8_array_to_array_370']?.()
-  __napiInstance.exports['__napi_register__i8_array_to_array_371']?.()
-  __napiInstance.exports['__napi_register__u16_array_to_array_372']?.()
-  __napiInstance.exports['__napi_register__i16_array_to_array_373']?.()
-  __napiInstance.exports['__napi_register__u32_array_to_array_374']?.()
-  __napiInstance.exports['__napi_register__i32_array_to_array_375']?.()
-  __napiInstance.exports['__napi_register__f32_array_to_array_376']?.()
-  __napiInstance.exports['__napi_register__f64_array_to_array_377']?.()
-  __napiInstance.exports['__napi_register__u64_array_to_array_378']?.()
-  __napiInstance.exports['__napi_register__i64_array_to_array_379']?.()
-  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_380']?.()
-  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_and_buffer_slice_381']?.()
-  __napiInstance.exports['__napi_register__AsyncBuffer_impl_382']?.()
-  __napiInstance.exports['__napi_register__async_reduce_buffer_383']?.()
-  __napiInstance.exports['__napi_register__async_buffer_to_array_384']?.()
-  __napiInstance.exports['__napi_register__u_init8_array_from_string_385']?.()
-  __napiInstance.exports['__napi_register__AsyncReader_impl_386']?.()
-  __napiInstance.exports['__napi_register__Reader_struct_387']?.()
-  __napiInstance.exports['__napi_register__Reader_impl_389']?.()
+  __napiInstance.exports['__napi_register__buffer_with_async_block_366']?.()
+  __napiInstance.exports['__napi_register__array_buffer_pass_through_367']?.()
+  __napiInstance.exports['__napi_register__accept_slice_368']?.()
+  __napiInstance.exports['__napi_register__accept_arraybuffer_369']?.()
+  __napiInstance.exports['__napi_register__create_arraybuffer_370']?.()
+  __napiInstance.exports['__napi_register__u8_array_to_array_371']?.()
+  __napiInstance.exports['__napi_register__i8_array_to_array_372']?.()
+  __napiInstance.exports['__napi_register__u16_array_to_array_373']?.()
+  __napiInstance.exports['__napi_register__i16_array_to_array_374']?.()
+  __napiInstance.exports['__napi_register__u32_array_to_array_375']?.()
+  __napiInstance.exports['__napi_register__i32_array_to_array_376']?.()
+  __napiInstance.exports['__napi_register__f32_array_to_array_377']?.()
+  __napiInstance.exports['__napi_register__f64_array_to_array_378']?.()
+  __napiInstance.exports['__napi_register__u64_array_to_array_379']?.()
+  __napiInstance.exports['__napi_register__i64_array_to_array_380']?.()
+  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_381']?.()
+  __napiInstance.exports['__napi_register__accept_uint8_clamped_slice_and_buffer_slice_382']?.()
+  __napiInstance.exports['__napi_register__AsyncBuffer_impl_383']?.()
+  __napiInstance.exports['__napi_register__async_reduce_buffer_384']?.()
+  __napiInstance.exports['__napi_register__async_buffer_to_array_385']?.()
+  __napiInstance.exports['__napi_register__u_init8_array_from_string_386']?.()
+  __napiInstance.exports['__napi_register__AsyncReader_impl_387']?.()
+  __napiInstance.exports['__napi_register__Reader_struct_388']?.()
+  __napiInstance.exports['__napi_register__Reader_impl_390']?.()
 }
 module.exports.Animal = __napiModule.exports.Animal
 module.exports.AnimalWithDefaultConstructor = __napiModule.exports.AnimalWithDefaultConstructor
@@ -477,6 +478,7 @@ module.exports.bigintGetU64AsString = __napiModule.exports.bigintGetU64AsString
 module.exports.btreeSetToJs = __napiModule.exports.btreeSetToJs
 module.exports.btreeSetToRust = __napiModule.exports.btreeSetToRust
 module.exports.bufferPassThrough = __napiModule.exports.bufferPassThrough
+module.exports.bufferWithAsyncBlock = __napiModule.exports.bufferWithAsyncBlock
 module.exports.buildThreadsafeFunctionFromFunction = __napiModule.exports.buildThreadsafeFunctionFromFunction
 module.exports.buildThreadsafeFunctionFromFunctionCalleeHandle = __napiModule.exports.buildThreadsafeFunctionFromFunctionCalleeHandle
 module.exports.call0 = __napiModule.exports.call0
diff --git a/examples/napi/index.cjs b/examples/napi/index.cjs
index 8eb015ab..3b23ac1e 100644
--- a/examples/napi/index.cjs
+++ b/examples/napi/index.cjs
@@ -434,6 +434,7 @@ module.exports.bigintGetU64AsString = nativeBinding.bigintGetU64AsString
 module.exports.btreeSetToJs = nativeBinding.btreeSetToJs
 module.exports.btreeSetToRust = nativeBinding.btreeSetToRust
 module.exports.bufferPassThrough = nativeBinding.bufferPassThrough
+module.exports.bufferWithAsyncBlock = nativeBinding.bufferWithAsyncBlock
 module.exports.buildThreadsafeFunctionFromFunction = nativeBinding.buildThreadsafeFunctionFromFunction
 module.exports.buildThreadsafeFunctionFromFunctionCalleeHandle = nativeBinding.buildThreadsafeFunctionFromFunctionCalleeHandle
 module.exports.call0 = nativeBinding.call0
diff --git a/examples/napi/index.d.cts b/examples/napi/index.d.cts
index da567b11..68158323 100644
--- a/examples/napi/index.d.cts
+++ b/examples/napi/index.d.cts
@@ -325,6 +325,8 @@ export declare function btreeSetToRust(set: Set<string>): void
 
 export declare function bufferPassThrough(buf: Buffer): Promise<Buffer>
 
+export declare function bufferWithAsyncBlock(buf: Buffer): Promise<number>
+
 export declare function buildThreadsafeFunctionFromFunction(callback: (arg0: number, arg1: number) => number): void
 
 export declare function buildThreadsafeFunctionFromFunctionCalleeHandle(callback: () => void): void
diff --git a/examples/napi/src/typed_array.rs b/examples/napi/src/typed_array.rs
index 2ccb2e3c..8aef5de1 100644
--- a/examples/napi/src/typed_array.rs
+++ b/examples/napi/src/typed_array.rs
@@ -1,3 +1,5 @@
+use std::sync::Arc;
+
 use napi::{bindgen_prelude::*, JsArrayBuffer};
 
 #[napi]
@@ -73,6 +75,16 @@ async fn buffer_pass_through(buf: Buffer) -> Result<Buffer> {
   Ok(buf)
 }
 
+#[napi]
+fn buffer_with_async_block(env: Env, buf: Arc<Buffer>) -> Result<AsyncBlock<u32>> {
+  let buf_to_dispose = buf.clone();
+  AsyncBlockBuilder::with(async move { Ok(buf.len() as u32) })
+    .with_dispose(move |_| {
+      drop(buf_to_dispose);
+    })
+    .build(env)
+}
+
 #[napi]
 async fn array_buffer_pass_through(buf: Uint8Array) -> Result<Uint8Array> {
   Ok(buf)