Mahmudul Islam

Blog

Short, practical notes from my day-to-day work: backend design, Python and TypeScript, LLM and RAG in production, and the tools around them. Posts are in English or German. Subscribe via RSS.

  1. Circuit breakers: failing fast when a dependency is down

    When a downstream service is struggling, waiting on it makes things worse. A circuit breaker stops calling it for a while so both sides can recover.

    3 min read

  2. Retrying failed requests with exponential backoff and jitter

    A retry loop can rescue a request or take down a struggling service. Here is how to retry with backoff, jitter and a budget so it does the first.

    2 min read

  3. Zero-downtime schema migrations with expand and contract

    Old and new code run side by side during every deploy. Here is how to change a database schema in small, safe steps so neither version breaks.

    3 min read

  4. Graceful shutdown: handling SIGTERM without dropping requests

    Every deploy stops your old processes. Here is how to handle SIGTERM so in-flight requests finish, connections close cleanly and users never notice.

    3 min read

  5. Structured logging: why your logs should be JSON

    Plain text logs are easy to write and hard to search. Here is how structured logs with consistent fields make debugging production services faster.

    2 min read

  6. Liveness vs readiness: writing health checks that actually help

    What liveness and readiness checks are for, why mixing them up causes restart loops, and how to write health endpoints that tell your platform the truth.

    3 min read

  7. Database connection pooling: what it is and how to size it

    Why opening a database connection per request hurts, how a connection pool fixes it, and how to choose pool sizes that do not overload your database.

    3 min read

  8. Rate limiting APIs with the token bucket algorithm

    How the token bucket works, why it handles bursts better than a fixed window, and what to think about when you run it across several servers.

    3 min read

  9. Smaller Docker images with multi-stage builds

    How multi-stage Dockerfiles keep compilers and dev dependencies out of your final image, with a simple Node example and a few habits that help.

    2 min read

  10. HTTP caching basics: Cache-Control and ETags

    How browsers and proxies decide when to reuse a response, and how Cache-Control and ETags let your API skip work it has already done.

    3 min read

  11. Access tokens and refresh tokens: why APIs use two

    A short-lived access token plus a longer-lived refresh token is a common login pattern. Here is what each one does and how to handle them safely.

    3 min read

  12. Database indexes, explained without the magic

    Indexes fix slow queries but can slow down writes. What they actually do, and how to decide when one is worth it.

    2 min read

  13. Idempotent APIs and why retries should be safe

    Networks fail in awkward ways. Designing endpoints so that a repeated request does no extra harm is one of the cheapest reliability wins you can get.

    2 min read

  14. Why I'm writing one short post every day

    A daily engineering log: what I learn building backend and LLM features in production, written down while it's still fresh.

    1 min read

  15. AI and the future of industry

    Where AI is already useful in manufacturing, healthcare, software, logistics and energy, how work is changing, and what responsible use looks like.

    2 min read

  16. Typed configuration in FastAPI with pydantic-settings

    Load and validate environment variables once, fail fast on bad config, and keep secrets out of your code: a small pattern I use in every FastAPI service.

    1 min read