Using WebAssembly (Wasm) at the Edge
Learn how to use WebAssembly (Wasm) to enable low-level languages to run on Vercel Edge Functions and Vercel Edge Middleware.WebAssembly, or Wasm, is a portable, low-level, assembly-like language that can be used as a compilation target for languages like C, Go, and Rust. Wasm was built to run more efficiently on the web and to run alongside JavaScript, so runs in most JavaScript virtual machines.
With Vercel, this means that you can now use Wasm within Edge Functions or Edge Middleware, taking advantage of the speed of delivery in a multitude of languages.
Pre-compiled WebAssembly can be imported with the ?module
suffix. This will provide an array of the Wasm data that can be instantiated using WebAssembly.instantiate()
.
While WebAssembly.instantiate
is supported in Edge Runtime, it requires the
Wasm source code to be provided using the import statement. This means you
cannot use a buffer or byte array to dynamically compile the module at
runtime.
You can use Wasm in your production deployment or locally, using vercel dev
.
-
You should already have an existing C, Go, and Rust project. This should be compiled it to WebAssembly to create a binary
.wasm
file. Once you have this.wasm
, you can use it in your Edge Function or Middleware -
Import the file into your existing project using:
api/wasm.tsimport wasmModule from './my-file.wasm?module';
-
Instantiate it:
api/wasm.tsexport const config = { runtime: 'edge', }; export default async function handler() { const { exports } = (await WebAssembly.instantiate(wasmModule)) as any; const result = exports.xor(0xb4c9a91f, 0xf0c0ffee); return new Response(result); }
This walkthrough uses the WASM XOR Edge API Route example.
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