Setting Up Subtrace in Cloudflare Workers

Here’s a quick guide to setting up Subtrace in your Cloudflare Workers. First, add @subtrace/cloudflare to your Worker package.json:

npm install @subtrace/cloudflare

Wrap your Worker’s fetch handler to use the Subtrace middleware:

src/index.js

import { subtrace } from "@subtrace/cloudflare";

export default {
  fetch: subtrace(async (request, env, ctx) => {
    return new Response("Hello World!");
  }),
};

Set a SUBTRACE_TOKEN environment variable in your Wrangler config file:

wrangler.jsonc

{
  "name": "my-worker",
  "main": "src/index.js",
  "compatibility_date": "2025-09-27",
  "vars": {
    // Go to https://subtrace.dev/dashboard to generate a token
    "SUBTRACE_TOKEN": "subt_..."
  }
}

Deploy your Cloudflare Worker:

npx wrangler deploy

And that’s it, you can now see all inbound and outbound HTTP requests in your Cloudflare Worker via the Subtrace dashboard!

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