Railway: deployment failing silently [2026 fix]
Railway builds succeed but services don't start; caused by missing PORT env var or broken health checks—add PORT=$PORT to start command.
Railway: Deployment Failing Silently [2026 Fix]
TL;DR
Cause: Your app builds successfully but crashes on startup because Railway can't find an open PORT or your health check times out.
Fix: Add PORT=${PORT} to your start command and ensure your app listens on the correct port.
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Real Console Error Messages
Here are exact error patterns you'll see in Railway logs:
``` [error] Application failed to start [error] Health check failed: connection refused on port 3000 [error] No process is listening on the assigned port [error] Deployment marked healthy but process exited with code 1 [error] listen EADDRINUSE: address already in use :::8080 ```
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Code Comparison: Broken vs Fixed
❌ BROKEN: Missing PORT Environment Variable
railway.json or Procfile: ```json { "build": { "builder": "nixpacks" }, "deploy": { "startCommand": "npm start" } } ```
package.json: ```json { "scripts": { "start": "node server.js" } } ```
server.js: ```javascript const app = require('express')();
app.listen(3000, () => { console.log('Server running on port 3000'); }); ```
✅ FIXED: Explicit PORT Variable + Dynamic Port
railway.json: ```json { "build": { "builder": "nixpacks" }, "deploy": { "startCommand": "PORT=${PORT} npm start", "healthcheck": { "path": "/health", "interval": 10, "timeout": 5 } } } ```
server.js: ```javascript const express = require('express'); const app = express(); const PORT = process.env.PORT || 3000;
app.get('/health', (req, res) => { res.status(200).json({ status: 'ok' }); });
app.listen(PORT, '0.0.0.0', () => {
console.log(Server running on port ${PORT});
});
```
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Why This Happens
Railway dynamically assigns ports at runtime—your app doesn't know in advance which port to use. When your code hardcodes 3000 but Railway assigns 8080, the health check fails and the container is killed silently without clear error output.
Key differences in Railway deployments:
1. PORT is injected at runtime via environment variables 2. Health checks run within 30 seconds of startup 3. Logs may be buffered, making failures appear "silent" 4. 0.0.0.0 binding is required to listen on all interfaces
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Step-by-Step Fix
1. Update your start command in railway.json or Procfile:
```
startCommand: "PORT=${PORT} node server.js"
```
2. Read PORT from environment in your app code: ```javascript const PORT = process.env.PORT || 3000; ```
3. Bind to 0.0.0.0, not localhost: ```javascript app.listen(PORT, '0.0.0.0', callback); ```
4. Add a health check endpoint: ```javascript app.get('/health', (req, res) => res.status(200).send('ok')); ```
5. Redeploy and check Railway logs for Server running on port message.
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Still Broken? Check These Too
1. [Node version mismatch](/?guide=nodejs-version) – Railway may use Node 18 while your code requires 20. Specify engines.node in package.json or create a .nvmrc file.
2. [Database connection timeouts](/?guide=railway-db-timeout) – If your app waits for a database before starting, Railway's 30-second health check window expires. Add connection retry logic with exponential backoff.
3. Process manager conflicts – PM2, nodemon, or Forever may fork processes that don't inherit the PORT variable. Use plain node or ensure your process manager passes env vars to children.
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Version Specificity
I am uncertain about: The exact timeout threshold for health checks—Railway's documentation mentions 30 seconds, but this may vary by plan tier in 2026. Test with console.time() and console.timeEnd() to measure startup duration.
I am confident about: The PORT environment variable injection, 0.0.0.0 binding requirement, and the need for explicit health check endpoints.
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Official References
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Found a different variation? Drop it in the comments—does your app fail with a different PORT scenario or custom health check config? Let's crowdsource the Railway edge cases.