Hello World

The simplest Thunder edge function. It responds to every request with a plain-text greeting.

Code

examples/hello/hello.ts

import { TextResponse } from "thunder:http";

export default function handler(req: Request) {
  return TextResponse("Hello from edge function!").toResponse();
}

The export default function pattern is the preferred way to define a Thunder edge function with a single handler. Thunder invokes the exported function for every inbound HTTP request routed to this function. The function receives a standard Request object and must return a Response (or a Promise<Response>).

The TextResponse helper from the thunder:http module creates a response with content-type: text/plain automatically. You can also chain .status() and .header() before .toResponse() for further customization.

Run locally

Start the function with hot-reload:

thunder watch --path ./examples/hello/hello.ts

Then test it:

curl http://localhost:9000/
# Hello from edge function!

Bundle

Create an eszip bundle for deployment:

thunder bundle --entrypoint ./examples/hello/hello.ts --output ./hello.eszip

Or a snapshot bundle (faster cold starts):

thunder bundle --entrypoint ./examples/hello/hello.ts --output ./hello.snapshot.bundle --format snapshot

Deploy

Deploy the bundle to a running Thunder server via the admin API:

curl -X POST http://localhost:9001/functions \
  -H "Content-Type: application/octet-stream" \
  -H "X-Function-Name: hello" \
  --data-binary @./hello.eszip

Invoke

Once deployed, invoke the function through the ingress listener:

curl http://localhost:9000/hello
# Hello from edge function!

What to try next

• Return JSON instead of plain text — see JSON API.
• Use the export default object pattern with HTTP method handlers — see RESTful CRUD.
• Explore all 30 examples in the Examples overview.