Backend engineering notes by Mohammed Mostafa on Node.js, TypeScript, Express.js, API architecture, message queues (BullMQ / Redis), authentication and payment-token security, and real-time systems (WebSockets, SSE, CRDTs) on AWS. Practical write-ups with code and diagrams from real projects like Lesoll, EgyStay, and SRVJ.
A workflow that zips the repository to S3 on every push, and the uncomfortable question underneath it: git already backs up your code. On provider independence as the real threat model, why the cadence was wrong, and why a backup you have never restored from is a hypothesis.
A deliberately boring production log pipeline: Pino writes NDJSON to disk, a UTC cron job rotates the file and reopens the descriptor, a gzipped archive goes to S3 with checksum verification, and the local copy is deleted only after the object is confirmed — with S3 Lifecycle enforcing retention.
How SRVJ's deployment grew up in three acts — a single EC2 box with NGINX and pm2, Docker Compose, and finally a Kubernetes cluster with kustomize, an NGINX ingress, and an HPA. Plus the S3 patterns that outlived every stage.