Railway: deployment failing silently [2026 fix]

Build succeeds but app crashes instantly; add Railway environment variables and check Procfile format immediately.

Railway: Deployment Failing Silently – Emergency Fix Guide

TL;DR

---

Real Console Error Messages

Here are exact error patterns you'll see in Railway's deploy logs:

``` [1] Error: listen EADDRINUSE :::3000 at Server.setupListenHandle [as _listen2] (net.js:1058:16) ```

``` [2] Cannot find module 'dotenv' from '/app/src/index.js' Require stack: /app/src/index.js ```

``` [3] Build successful but container exits immediately with code 137 (Memory limit exceeded or process killed) ```

``` [4] No start script found. Railway cannot determine entry point. Check package.json 'scripts.start' field. ```

``` [5] /bin/sh: 1: web: command not found (Procfile format broken) ```

---

The Core Issue: Environment Variables & Boot Config

Railway's deployment *appears* successful because the build phase completes. However, your app fails instantly during the runtime phase because:

1. Missing PORT variable – Node tries to bind to a hardcoded port that conflicts 2. Broken Procfile – Entry point syntax is wrong 3. Dependencies not installed – Build caching skips node_modules install 4. Runtime env vars missing – Database URLs, API keys aren't injected

---

Broken vs. Fixed Code

Problem 1: Hardcoded Port

BROKEN: ```javascript // server.js const express = require('express'); const app = express();

app.listen(3000, () => { console.log('Server running on port 3000'); }); ```

FIXED: ```javascript // server.js const express = require('express'); const app = express(); const PORT = process.env.PORT || 3000;

app.listen(PORT, () => { console.log(Server running on port ${PORT}); }); ```

---

Problem 2: Missing/Broken Procfile

BROKEN: ```

Procfile (syntax error – space after colon missing)

FIXED: ```

Procfile (correct format)

Note: Procfile must be in your repo root, not in a subdirectory.

---

Problem 3: package.json Missing Start Script

BROKEN: ```json { "name": "my-app", "version": "1.0.0", "scripts": { "dev": "node server.js" } } ```

FIXED: ```json { "name": "my-app", "version": "1.0.0", "scripts": { "start": "node server.js", "dev": "node server.js" } } ```

Railway prioritizes: Procfile → package.json start script → auto-detection.

---

Problem 4: Environment Variables Not Injected

BROKEN: ```javascript // index.js – assumes DATABASE_URL exists const db = require('pg').Pool({ connectionString: process.env.DATABASE_URL }); // Railway deploys but app crashes: "Cannot read property 'query' of undefined" ```

FIXED: ```javascript // index.js require('dotenv').config();

const db = new (require('pg')).Pool({ connectionString: process.env.DATABASE_URL || 'postgresql://localhost/dev' });

if (!process.env.DATABASE_URL && process.env.NODE_ENV === 'production') { throw new Error('DATABASE_URL is required in production'); } ```

Also add to Railway dashboard: 1. Navigate to your project 2. Settings → Variables 3. Add DATABASE_URL, API_KEY, etc.

---

Quick Diagnostics

Check Railway logs in real-time: ```bash

Install Railway CLI

Login

View live logs

Check current env vars

Version note: As of Railway's 2024-2026 updates, the CLI behavior for variable display changed slightly, but railway logs has remained stable.

---

Still Broken? Check These Too

1. Node Version Mismatch – Specify engines.node in package.json. Railway uses Node 18+ by default; if your code requires Node 16, add "engines": {"node": "16.x"} to package.json and redeploy.

2. Build Command Override – If Railway auto-detects wrong build command, add railway.json to root: ```json {"buildCommand": "npm run build", "startCommand": "npm start"} ``` (I'm uncertain if this exact format persists in all Railway versions—verify in [official docs](https://docs.railway.app/deploy/builds))

3. Memory Limits – Exit code 137 = OOM killed. Check your app's memory usage locally with node --inspect and upgrade Railway's resource tier if needed.

---

Official Documentation

For the authoritative source: [Railway Deployment Docs](https://docs.railway.app/deploy/railway-json)

Related Guides

---

Found a different variation? Drop it in the comments below – Railway's failure modes evolve with each release.