I'm Santosh Kumar, a full stack developer in Patna, India. I write about the things I build with — Next.js, Node.js, AWS and the parts of shipping web apps that tutorials skip.
· 5 min read
A production-ready setup for Node.js on a single EC2 instance — PM2 cluster mode, Nginx reverse proxy with free HTTPS, and push-to-deploy with GitHub Actions and zero-downtime reloads.
· 10 min read
A practical guide to MySQL connection pools in Node.js — how pools work, every mysql2 option that matters, safe transactions, finding connection leaks, and sizing pools across cluster workers and containers.
· 6 min read
How I serve every user's portfolio from their own subdomain or custom domain in one Next.js app — middleware rewrites, DNS verification, Vercel's domains API and the SEO traps.
· 9 min read
Running the Node.js cluster module in a container has traps a VM doesn't — os.cpus() lies about your CPU limit, Node as PID 1 ignores signals, and docker stop kills workers mid-request. Here's how to do it right.
· 8 min read
Node.js runs your JavaScript on one thread, so one process uses one core. A practical guide to the cluster module — forking workers, crash recovery, zero-downtime restarts and the shared-state traps.
· 5 min read
In-memory rate limiters don't work on serverless. Here's a 30-line rate limiter built on MongoDB's atomic upserts and TTL indexes, the trade-offs, and when to switch to Redis.
· 6 min read
Stop streaming uploads through your server. A practical guide to S3 presigned PUT and POST uploads with the AWS SDK v3 — validation, size limits, CORS and the security details that matter.