Deploying a Node service

In plain English

Deploying a server means running it somewhere other than your laptop, so it must behave well under a process manager. Build dependencies such as a compiler or test runner are needed only while building, while runtime dependencies are needed to run the service. A health endpoint is a small route that returns ok so a load balancer can tell whether the service is alive. Graceful shutdown means stopping new requests and finishing in-flight ones when the process receives a signal such as SIGTERM. Structured logs and environment variables keep the deployed service configurable and observable.

Step by step

1. 1Install build tools as dev dependencies so production installs skip them.
2. 2Add a /health route that reports the service state.
3. 3Listen for SIGTERM and SIGINT and close the server.
4. 4Set a timeout so a stuck server still exits eventually.

import { createServer } from 'node:http'

const port = Number(process.env.PORT ?? 3000)

const server = createServer((request, response) => {
  if (request.url === '/health') {
    response.writeHead(200, { 'content-type': 'application/json' })
    return response.end(JSON.stringify({ status: 'ok' }))
  }
  response.writeHead(404)
  response.end()
})

server.listen(port, () => {
  console.log('Listening on ' + port)
})

function shutdown(signal: string) {
  console.log('Received ' + signal + ', closing server')
  server.close(() => {
    console.log('Server closed')
    process.exit(0)
  })
  setTimeout(() => {
    console.error('Forced shutdown after timeout')
    process.exit(1)
  }, 10_000).unref()
}

process.on('SIGTERM', () => shutdown('SIGTERM'))
process.on('SIGINT', () => shutdown('SIGINT'))

Common mistakes

• Shipping test runners and compilers to production bloats the image and widens the attack surface.
• Ignoring SIGTERM makes a deploy kill the process mid-request and lose work.
• Returning ok from /health even when the database is down hides a real outage.
• Hard-coding ports and URLs means the service cannot move between environments.