When a rewrite isn’t: rebuilding Slack on the desktop. Slack appear to have pulled off the almost impossible: finishing a complete, incremental rewrite of their core product. They moved from jQuery to React over the course of two years, constantly shipping new features as they went along. The biggest gain was in rewriting their code to support multiple workspaces, which means desktop client users no longer have to run a separate copy of Electron for every workspace they are signed into.
Recent articles
- Reverse engineering Codex CLI to get GPT-5-Codex-Mini to draw me a pelican - 9th November 2025
- Video + notes on upgrading a Datasette plugin for the latest 1.0 alpha, with help from uv and OpenAI Codex CLI - 6th November 2025
- Code research projects with async coding agents like Claude Code and Codex - 6th November 2025