# WebAssembly64


WebAssembly64 lets Unity Web builds grow the WebAssembly heap up to 16 GB by using the [WebAssembly Memory64](https://github.com/WebAssembly/memory64/blob/main/proposals/memory64/Overview.md) extension. Although 64-bit pointers allow a much larger address space, Unity Web builds are currently limited to 16 GB by the [WebAssembly JavaScript API specification](https://www.w3.org/TR/wasm-js-api-2/#limits).

Use WebAssembly64 only if your application requires more than 4 GB of memory. This feature can increase code size and runtime overhead.

> **Note:**
>
> Using WebAssembly64 automatically enables [WebAssembly 2023](/engine/6000.7/manual/platform-specific/webgl/develop/webassembly-2023.md).

If your project uses native or JavaScript plug-ins, make them compatible with WebAssembly64 before you build. For more information, refer to [Web native plug-ins for Emscripten](/engine/6000.7/manual/platform-specific/webgl/develop/native-plugins-with-emscripten.md) and [Call JavaScript functions from Unity C# scripts](/engine/6000.7/manual/platform-specific/webgl/develop/interactingwithbrowserscripting/web-interacting-browser-js-to-unity.md).

| **Topic**                                                                                                                            | **Description**                                                         |
| ------------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------- |
| [**Prerequisites for WebAssembly64**](/engine/6000.7/manual/platform-specific/webgl/develop/wasm-64bit-support/wasm-64bit-prereq.md) | Learn what browser you need to use for WebAssembly64.                   |
| [**Enable WebAssembly64**](/engine/6000.7/manual/platform-specific/webgl/develop/wasm-64bit-support/wasm-64bit-enable.md)            | Enable WebAssembly64 so Unity Web builds can use up to 16 GB of memory. |

## Additional resources

* [Web](/engine/6000.7/manual/platform-specific/webgl.md)
* [Web Player settings](/engine/6000.7/manual/platform-specific/webgl/develop/class-player-settings-web-gl.md)
* [Prerequisites for WebAssembly 2023](/engine/6000.7/manual/platform-specific/webgl/develop/webassembly-2023/wasm-2023-prereq.md)