# OPENAI DROPPED A PDF ON HOW THEY USE CODEX INTERNALLY and it's actually usefu...
Canonical: https://social-archive.org/yena/UGhFsQxN0t
Original URL: https://x.com/_vmlops/status/2057080944465748109
Author: Vaishnavi
Platform: x
## Content
OPENAI DROPPED A PDF ON HOW THEY USE CODEX INTERNALLY and it's actually useful their engineers across security, infra, frontend, and api teams use it daily for: ▫️ understanding unfamiliar codebases fast (especially during incidents) ▫️ refactoring changes that span dozens of files ▫️ generating tests for edge cases devs usually miss ▫️ scaffolding boilerplate so you ship faster ▫️ staying in flow when your calendar is a disaster the one that hit different: one engineer said "i was in meetings all day and still merged 4 PRs because codex was working in the background" https://cdn.openai.com/pdf/6a2631dc-783e-479b-b1a4-af0cfbd38630/how-openai-uses-codex.pdf