React on the Edge

sveltekit-on-the-edge but on top of React. It uses esbuild for bundling and Vercel Edge Functions for SSR.

This example is for framework builders and advanced usage of the low-level Vercel Build Output API. If you’re looking to develop a React application with dynamic Edge capabilities, we recommend Next.js Middleware and Vercel Edge Functions.

How to use

Run pnpm i then:

  • To build: pnpm build
  • To run a local server: pnpm start

To build this demo with streaming (renderToStream) instead of renderToString run USE_STREAMS=1 pnpm build.
After building, .vercel/output will be created which you can deploy via vc --prebuilt.


  • util/build.mjs implements the build process on top of esbuild that bundles src/app into an Edge Function.
  • util/start.mjs implements a local server using the edge-runtime package that can locally run the build outputs.


Due to the absence of a dev server, watchexec can be used as a replacement. Use brew install watchexec to install.

watchexec -c -r --no-meta 'node util/build.mjs; node util/start.mjs'


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