what code base did stripe convert with claude fable to what langauge

Stripe reportedly used Claude Fable 5 on a 50-million-line Ruby codebase , and the migration was described as a Ruby migration completed in one day.

Quick Scoop

• Codebase: Ruby, around 50 million lines.

• Result: A large migration that Stripe said would have taken about two months by hand was finished in one day.

One nuance

Some posts phrase it as “the codebase Stripe converted with Claude Fable,” but the clearest reporting points to a Ruby codebase rather than a move to a different language.

TL;DR: Stripe’s Claude Fable story was about a massive Ruby-to-Ruby migration/cleanup , not a famous “converted to X language” switch.