HOW SLACK REBUILT NOTIFICATIONS 📣

Summary from the TLDR Dev newsletter

Slack's notification system had quietly become a mess due to four conflicting preference models, settings that didn't sync across devices, and no clean way to separate “show me activity” from “push me.” They rebuilt it from scratch into one unified model with a simple three-option structure and a single boolean controlling push, migrating millions of users without downtime using a read-time remapping strategy.