auto-relay

A CLI tool that auto-discovers your Express.js routes and lets you explore and test them in the browser — no changes needed in your app code.

Install the package, run two commands, done.

Current support: Node.js + Express.js

Install

npm install --save-dev @bhaskardey772/auto-relay

Usage

Step 1 — Initialize config

npx auto-relay init

This creates auto-relay.config.js in your project root:

module.exports = {
  rootDir: './',                        // directory to scan for routes
  port: 4000,                           // port for the relay explorer
  baseUrl: 'http://localhost:3000',     // your running Express app's URL
  exclude: [],
  title: 'Auto Relay',
};

Step 2 — Start your app as usual

node app.js   # or npm start, nodemon, etc.

Step 3 — Start the relay

npx auto-relay start

Open http://localhost:4000 in your browser — all your routes are there, ready to test.

What you get

• Sidebar — all Express routes auto-detected, grouped by file or HTTP method
• Filter & group — live-filter routes, toggle between file/method grouping
• Request builder — path params, query params, custom headers, bearer token field, JSON body editor
• Body pre-fill — req.body fields auto-detected from handler source code and pre-populated
• Response viewer — syntax-highlighted JSON, raw text, response headers, status, timing, size
• Variables — {{VAR_NAME}} placeholders in any field; BASE_URL seeded automatically
• Rescan — re-discover routes without restarting anything
• State persistence — inputs saved per-route in localStorage

Options

// auto-relay.config.js
module.exports = {
  rootDir: './',                        // directory to scan (default: process.cwd())
  port: 4000,                           // relay server port (default: 4000)
  baseUrl: 'http://localhost:3000',     // your app's base URL
  exclude: ['tests/**', 'mocks/**'],    // extra glob patterns to skip
  title: 'Auto Relay',                  // browser tab title
};

| Option | Type | Default | Description | |-----------|------------|-------------------------|------------------------------------------------| | rootDir | string | process.cwd() | Root directory to scan for Express routes | | port | number | 4000 | Port the relay explorer runs on | | baseUrl | string | http://localhost:3000 | Base URL of your running Express app | | exclude | string[] | [] | Extra glob patterns to skip during scanning | | title | string | Auto Relay | Title shown in the browser tab and header |

CLI flags

npx auto-relay start --port=5000   # override port from CLI

How it differs from auto-detect-route

| | auto-detect-route | auto-relay | |---|---|---| | Setup | Add middleware to your Express app | Install package + run CLI | | Changes to your app | Yes — app.use('/explorer', ...) | None | | Runs | Inside your app process | Separate process, separate port | | Config | Options passed to middleware | auto-relay.config.js file |

Use auto-relay when you don't want to touch your app code at all.

How it works

auto-relay start reads your config, then:

1. Scans your source files using AST parsing (@typescript-eslint/typescript-estree) — same engine as the auto-detect-route package.
2. Starts a standalone Express server on the configured port.
3. Proxies requests from the browser UI to your running app — no CORS issues.

The scan uses a 3-pass algorithm: parse all files → find entry points → DFS across require()/import chains to resolve full route paths including nested router prefixes.

Security

• Sensitive files (.env, .key, .pem, credentials) are never read by the scanner
• Only http: and https: protocols are allowed in the proxy
• Response bodies are capped at 10 MB
• Keep the relay server on localhost — do not expose it publicly

License

MIT