Writing

Notes from building software products.

How the hard parts of my projects work: rate limiting, realtime delivery, background jobs. Short, with the code that matters. Papers and datasets are under Research, and every post is in the RSS feed.

1. 18 Oct 2026·3 min read·LimitYourAPI

   How Redis rate limiters fail under load, measured

   I measured eight Redis rate limiter designs in 3,853 trials. Check-then-act let 29% too much through, WATCH refused up to 42% of good traffic, and caller clocks broke token buckets.

2. 18 Oct 2026·11 min read·LimitYourAPI

   Atomic rate limiting with Redis and Lua, measured

   Lua makes a Redis rate limiter atomic. I measured what that costs, and three ways the scripts still break: timestamp members that admit 12× the limit, keys Cluster rejects, and logs that stall Redis.

3. 18 Oct 2026·4 min read·PromptP

   Realtime without lost events: an append-only log and a cursor

   How PromptP uses Redis Streams as an append-only log so reconnecting clients replay exactly what they missed, and how per-socket backpressure keeps one slow client from stalling the rest.

4. 18 Oct 2026·2 min read·StartupDeckAI

   Keep the request path fast: AI generation in BullMQ workers

   Generating a pitch deck takes far longer than a web request should. How StartupDeckAI moves analysis and generation into BullMQ workers, with retries, progress and one job per idea.