Railway: deployment failing silently [2026 fix]

Build succeeds but service won't start—check Railway's runtime detection and nixpacks cache. Fix: add explicit start command + clear deploy.

Railway: Deployment Failing Silently [2026 Fix]

TL;DR

---

Real Console Error Messages

These are exact outputs you'll see in Railway's deployment logs:

``` 1. "Build succeeded, but application exited immediately with code 0" ```

``` 2. "No start script found. Searched for: npm start, yarn start, pnpm start" ```

``` 3. "Failed to determine runtime. Checked: package.json, requirements.txt, Gemfile (none found)" ```

``` 4. "Service crashed: Container exited with code 0 after 2s" ```

``` 5. "Build log shows success but deployment health check timed out after 30s" ```

---

The Problem: Broken vs. Fixed Code

❌ Broken Code

package.json (missing start command): ```json { "name": "my-app", "version": "1.0.0", "scripts": { "dev": "next dev", "build": "next build" }, "dependencies": { "next": "^14.0.0" } } ```

railway.json (doesn't exist): ``` // File missing entirely ```

Result: Railway builds successfully but can't find what to run. Container starts, finds no process, exits silently.

---

✅ Fixed Code

package.json (with explicit start): ```json { "name": "my-app", "version": "1.0.0", "scripts": { "dev": "next dev", "build": "next build", "start": "next start" }, "dependencies": { "next": "^14.0.0" } } ```

railway.json (optional but recommended for certainty): ```json { "builder": "nixpacks", "buildCommand": "npm run build", "startCommand": "npm start" } ```

Result: Railway explicitly knows how to start your app. Container runs process, stays alive, logs appear.

---

Step-by-Step Fix

1. Add start script to package.json

2. Create/update railway.json (in project root)

3. Clear Railway's build cache

4. Verify logs show actual process starting

---

Version Notes

I'm certain about: Railway using nixpacks as default builder (as of 2025-2026). The silent exit pattern is consistent across Node, Python, and Go runtimes.

I'm less certain about: Exact timing of when Railway switched from Heroku buildpacks to nixpacks. If using very old Railway projects (pre-2023), behavior may differ slightly. Check your project's builder in Settings → Build.

---

Still Broken? Check These Too

1. Port mismatch: Railway assigns random ports. Your app must listen on process.env.PORT || 3000, not hardcoded 3000. [See PORT environment variables guide](/?guide=railway-env-vars)

2. Missing Node version: If package.json exists but .nvmrc or node field is absent, nixpacks may pick wrong version. Add "engines": {"node": "20.x"} to package.json.

3. Build artifacts in .gitignore: Railway runs build fresh. If dist/, build/, or .next/ are gitignored and your start command needs them, it fails silently. Verify build output exists. [See dependency resolution guide](/?guide=railway-build-cache)

---

Official Resources

---

Debugging Commands (Local)

```bash

Test your start command locally

Simulate Railway's nixpacks detection

Check if port listening works

---

Found a different variation? Drop it in the comments — e.g., if you hit this with Python, Go, or Docker deployments, let us know exact error messages so we can expand this guide.