HTTP Endpoints

HTTP Endpoints

HTTP vals (fileType: "http") export a request handler and run on every incoming HTTP request. Each HTTP file is assigned a public live URL — never construct it yourself; read links.endpoint from list_files or create_file responses, or call fetch_val_endpoint.

Basic handler

// Learn more: https://docs.val.town/vals/http/
export default async function (req: Request): Promise<Response> {
  return Response.json({ ok: true });
}

The file must have an export — export default for the handler.

Hono

When using Hono, export app.fetch (not app):

import { Hono } from "npm:hono";

const app = new Hono();

app.get("/", (c) => c.text("hello"));

// Always add this for full stack traces on errors:
app.onError((err) => Promise.reject(err));

export default app.fetch;

serveStatic and cors middleware from Hono do not work on Val Town. Use serveFile / staticHTTPServer from std/utils for static files, and rely on Val Town's default CORS (see below). For the full std/utils API (readFile, serveFile, staticHTTPServer, listFiles, listFilesByPath, httpEndpoint, parseVal, …), fetch https://utilities.val.run/docs.md.

CORS

Val Town adds permissive CORS headers by default (Access-Control-Allow-Origin: *). If you set any CORS header yourself, Val Town stops adding all default headers — so either handle CORS completely yourself or don't touch it at all.

Redirects

Response.redirect is broken on Val Town. Use one of:

return new Response(null, { status: 302, headers: { Location: "/path" } });
// or, with Hono:
return c.redirect("/path");

What's not available

• WebSockets: Val Town does not accept incoming WebSocket connections. Use polling, long polling, or server-sent events instead.
• Filesystem access: see the platform constraints. For persistent state, use std/sqlite or std/blob.

Surfacing client-side errors

For HTML responses, add this script tag to send browser errors back to val logs (visible via get_logs):

<script src="https://esm.town/v/std/catch"></script>

Verifying changes

After editing an HTTP val, always call fetch_val_endpoint to confirm it returns the expected status and body. Do not report a change as done without this step.