Express

This guide covers adding debugger to an Express project. The setup takes one line.

Express official docs

Install

npm install -D @ephem-sh/debugger

Set up

Import and call instrumentExpress with your Express app:

import express from 'express'
import { instrumentExpress } from '@ephem-sh/debugger/express'

const app = express()
instrumentExpress(app)

This sets up the log store, IPC bridge, console patching, and HTTP middleware for the ingest endpoint and browser client script. It no-ops when NODE_ENV is production.

Browser support

The middleware automatically serves /_/d.js and handles POST /_/d for browser log ingestion. Add script tags before </body> in your HTML templates:

<script>window.__DEBUGGER_INGEST_URL__="/_/d";</script>
<script src="/_/d.js" defer></script>

Verify

node index.ts

npx dbg status

pnpm dlx dbg status

bun x dbg status

yarn dlx dbg status

npx dbg browser console

pnpm dlx dbg browser console

bun x dbg browser console

yarn dlx dbg browser console

npx dbg server console

pnpm dlx dbg server console

bun x dbg server console

yarn dlx dbg server console

Full example

See the complete working example at examples/node/expressjs.