How OpenAI Codex went from failed side project to 40M+ weekly users in under a year
every · x · 2026-10-16
Dan Shipper tells the inside story of OpenAI Codex: a year ago it was a scrappy effort in a quiet corner of OpenAI whose cloud product hadn't found PMF. Less than 12 months later:
- Codex swallowed the flagship ChatGPT desktop app from the inside (it literally runs as com.openai.codex on your Mac)
- Codex and ChatGPT for Work now claim 40M+ weekly users across engineering and knowledge work
- Its leader Thibault Sottiaux was elevated to run all of OpenAI's core products: ChatGPT, Codex, and the API
The key move: OpenAI trained a dedicated model line for Codex, separate from ChatGPT, with its own researchers and product team.
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