Redis in Practice: Who's Online? Using Redis to implement a “which of your friends are online now” feature, by maintaining a set of active user IDs for every minute, then intersecting the past five minutes of user IDs with a set containing the IDs of your friends.
Recent articles
- Highlights from my appearance on the Data Renegades podcast with CL Kao and Dori Wilson - 26th November 2025
- Claude Opus 4.5, and why evaluating new LLMs is increasingly difficult - 24th November 2025
- sqlite-utils 4.0a1 has several (minor) backwards incompatible changes - 24th November 2025