Stripe Formats Entire 25 Million Line Ruby Codebase Overnight with Rust-Based rubyfmt
Stripe Dev Blog / r/programming·medium signal
Stripe published a deep-dive on formatting their entire 25M-line Ruby codebase overnight using rubyfmt, a Rust-based zero-config autoformatter achieving sub-100ms per file. They mass-formatted 62,213 files in a single Saturday morning, used ripper-tree diffing for correctness validation, and later migrated to the Prism parser to eliminate the Ruby VM dependency entirely. The post (60 upvotes, 22 comments on r/programming) showcases infrastructure-scale tooling decisions at companies processing massive codebases.