Railway: deployment failing silently [2026 fix]
Railway deployments fail silently when build logs aren't checked and environment variables aren't synced to production.
Railway: Deployment Failing Silently [2026 Fix]
TL;DR
Cause: Your app exits successfully during the build phase but crashes immediately on startup because Railway isn't capturing stderr or your build command succeeded while the start command fails.
Fix: Add explicit logging to your start command and check Railway's Build & Deployment logs tab (not just the deployment summary) for hidden stderr output.
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Real Console Error Messages
These are the exact messages you'll see (or won't see) when this happens:
``` ✓ Build successful ✓ Deploy successful ```
*(Then your app is dead but Railway shows green.)*
``` error: listen EADDRINUSE: address already in use :::3000 ```
*(Hidden in logs tab, not in deployment output)*
``` Error: Cannot find module 'dotenv' at Module._load (internal/modules/commonjs_loader.js:1050:11) ```
``` FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory ```
``` TypeError: Cannot read property 'DATABASE_URL' of undefined ```
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Broken Code vs. Exact Fix
Problem 1: Silent Crashes on Startup
BROKEN: ```json { "scripts": { "build": "next build", "start": "next start" } } ```
FIXED: ```json { "scripts": { "build": "next build", "start": "node -e \"console.log('Starting...'); require('./dist/index.js')\" || (echo 'Start failed' && exit 1)" } } ```
*Or better: use explicit error handling in your entry point*
BROKEN (Node): ```javascript const express = require('express'); const app = express();
app.listen(PORT); // What if PORT is undefined? ```
FIXED: ```javascript const express = require('express'); const app = express();
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(✓ Server running on port ${PORT});
console.error('DEBUG: All env vars loaded');
});
process.on('uncaughtException', (err) => { console.error('FATAL ERROR:', err); process.exit(1); }); ```
Problem 2: Environment Variables Not Available at Runtime
BROKEN (Railway config): ```bash
In Railway dashboard, variables set in "Variables" tab
but NOT referenced in Dockerfile
FROM node:18 RUN npm install RUN npm run buildBuild succeeds, but DATABASE_URL is undefined at runtime
CMD ["npm", "start"] ```FIXED: ```bash FROM node:18 RUN npm install RUN npm run build
Explicitly tell Railway to pass env vars
ARG DATABASE_URL ARG NODE_ENV=production ENV NODE_ENV=$NODE_ENV ENV DATABASE_URL=$DATABASE_URL CMD ["npm", "start"] ```*Or in Railway dashboard: ensure variables are set in the Service Variables section, not just in the build logs.*
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How to Actually See the Errors
1. Go to Railway dashboard → Your project → Select service
2. Click "Deployment" tab → Find the stuck deployment
3. Scroll to "Build Logs" and "Runtime Logs" sections (NOT just the summary)
4. Search for: error, Error, FATAL, undefined
5. If empty, add this to your start command to force output:
```bash node -e "console.log(Object.keys(process.env))" && npm start ```
This will dump all available env vars before crashing, showing you what's missing.
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Still Broken? Check These Too
1. Port binding issue: Railway assigns a random $PORT env variable. Verify your app reads it:
```javascript
const PORT = process.env.PORT || 3000; // ← Must use process.env.PORT
```
See [Railway PORT binding guide](/?guide=railway-port) for details.
2. Health checks timeout: Railway kills services that don't respond within 60 seconds. If your build is slow or startup is slow, increase the health check timeout in Railway dashboard under Settings → Health Check.
3. Procfile ignored: If you have a Procfile, Railway reads it. If it's wrong, deployment succeeds silently but the process fails:
```bash
# WRONG
web: npm start
# CORRECT (must match your actual entry point)
web: node dist/index.js
```
4. Module not found post-build: Dependencies installed during build might not persist. Check that node_modules is included or use npm ci instead of npm install in Dockerfile.
5. Memory limits: Apps exceeding Railway's free tier memory (512MB) will be killed silently. Check Metrics tab to see actual usage vs. allocated.
See [related guide on Railway health checks](/?guide=railway-health-checks).
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Version Note
I'm explicitly uncertain about Railway's logging UI changes between early 2024 and 2026. The build/runtime logs tabs exist as of Q2 2025, but if Railway has refactored their dashboard, the log viewing location may differ. Always check your service's Logs section first; if missing, check Deployment Details for error traces.
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Official Resources
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