Rakkas projects can be built to run on Bun. First, you should install the suitable HatTip adapter:

npm install -S @hattip/adapter-bun

Then you should set the adapter option of Rakkas Vite plugin to "bun":

import { defineConfig } from "vite";
import rakkas from "rakkasjs/vite-plugin";

export default defineConfig({
  plugins: [
      adapter: "bun",

After building with rakkas build, you can run your project with bun run dist/server/entry-bun.js.


  • Bun doesn't support streaming, so streaming is disabled.
  • Bun doesn't have a Request.prototype.formData() implementation yet. Rakkas polyfills it using URLSearchParams so only application/x-www-form-urlencoded is supported. multipart/form-data is not supported.