Shipping a working app is great — keeping it working under real users is where the learning happens. Below are ten common production pitfalls I see again and again, with short, practical fixes you can apply today. If you want hands-on help turning these into code and deploy checks, consider mentor-reviewed full stack classes in Mumbai or a project-first https://www.sevenmentor.com/full-stack-classes-in-mumbai 1. Missing health checks and smoke tests Problem: Deploys succeed but core flows are broken. Fix: Add GET /health and a simple smoke script that logs in, creates an item, and lists it. Run this automatically after deploys. 2. Secrets accidentally committed Problem: API keys or DB URLs end up in git history. Fix: Use .env files, commit only .env.example, and rotate any secret that was committed. Add a pre-commit hook (or a CI scan) that blocks credentials. 3. No deploy rollbacks or tags Problem: Hard to revert a breaking release. Fix: Tag releases (v1.2.0) and keep a one-line rollback procedure in your runbook (how to revert to previous tag and run smoke tests). 4. Slow list endpoints (no pagination / no indexes) Problem: Lists time out with more data. Fix: Implement server-side pagination (limit + cursor) and add an index matching your WHERE + ORDER BY (e.g., (user_id, created_at)). 5. Authentication edge cases Problem: Refresh tokens, cookie domains, or SameSite flags break auth in prod. Fix: Use secure HttpOnly cookies for refresh tokens, test the flow end-to-end in staging, and document cookie domain & SameSite settings in README. 6. No observability (logs & metrics) Problem: You can’t tell what’s slow or failing. Fix: Emit structured logs (reqId, route, duration_ms), capture p95 for key endpoints, and add a single alert (error rate or p95) to Slack/email. 7. Heavy synchronous work in request handlers Problem: PDF generation, large uploads, or third-party calls slow user responses. Fix: Move heavy work to background jobs/queues (BullMQ, Sidekiq). Keep request handlers fast and return accepted/202 for long tasks with a job ID. 8. Inconsistent API contracts between client & server Problem: Front end crashes because the server returns a different shape than expected. Fix: Keep a small API contract doc (/docs/api.md) and add one integration test that asserts the shape the UI depends on. 9. No rate limiting on public endpoints Problem: Brute-force login attempts or abusive scraping. Fix: Add IP/user rate limits to login and public APIs. Consider simple exponential backoff after repeated failures. 10. Poorly documented runbook & recovery steps Problem: On-call becomes panic-mode because the “how to fix” is missing. Fix: Write a one-page runbook: how to run smoke tests, how to rollback, where logs live, who to ping. Keep it in the repo as RUNBOOK.md. Quick 7-point action list (do these right now) Add GET /health and a CI smoke test. Create .env.example and scan git history for secrets. Add one DB index for your largest list query. Add server-side pagination to all list endpoints. Emit structured logs with reqId for every request. Protect login with rate limiting and captcha fallback. Write RUNBOOK.md with rollback steps and a smoke-test command. Why mentorship speeds this up Applying these fixes once is useful — applying them reliably across projects and explaining them in interviews is what gets you hired. If you want guided code reviews, deployment checks, and a mentor to walk through observability and runbooks, check out full stack classes in Mumbai or enroll in a hands-on full stack classes in Mumbai . They’ll help you add these protections to your portfolio projects so you can show production-ready work to recruiters. Learn More: https://www.sevenmentor.com/full-stack-classes-in-mumbai