Express on Watt 3

Use @platformatic/node for an existing Express application. Preserve middleware, routers, error handling, and the project's ESM/CommonJS convention.

watt.json:

{
  "module": "@platformatic/node",
  "node": { "main": "./server.js" },
  "runtime": { "server": { "hostname": "0.0.0.0", "port": "{PORT}" } }
}

An ESM entrypoint can export a factory without starting a second listener:

import express from 'express'

export async function create () {
  const app = express()
  app.get('/health', (request, response) => response.json({ status: 'ok' }))
  return app
}

Install the matching major 3 Node capability and Watt with authorization. For CommonJS, export the factory through module.exports instead of converting the entire project.

Review trust proxy, cookies, redirects, body size limits, and mounted path prefixes behind a gateway. Server-side callers use http://<application-id>.plt.local. Use the framework's error-handling conventions and stable application error codes.

For a self-listening entrypoint, preserve one owner for listen() and provide a supported shutdown path for the HTTP server, timers, and external connections. Test startup, representative routes, and graceful shutdown after integration.

See integration and enterprise.