Blog

1. 01 27 Sep 2026

   Load-Testing a URL Shortener (opens in a new tab)

   Part 2 · Medium

   Pushing the linkpulse redirect path with k6 until something gave. A fixed VU test measures concurrency, not throughput, and at 3,000 requests a second one Node process ran out of CPU while Redis and Postgres sat at about 25%.

   • Programming
   • Node.js
   • Performance
2. 02 21 Aug 2026

   I Built a Twitter-Style Feed to Find Out What Fan-Out Actually Costs (opens in a new tab)

   Part 2 · Medium

   Push and pull feeds built over the same data and measured. Fan-out costs about 12 microseconds per follower, a timeline entry about 80 bytes in Redis, and the read advantage was far smaller than expected.

   • System Design Interview
   • Software Engineering
   • Backend