dif.sh

Every flag and every experiment in dif is one Markdown file, checked into git next to the code it changes. It gets reviewed in a pull request. Its history is the git history. When it is done, the decision and what you learned go in the same file.

The alternative is what most teams have now. Flags live in a web dashboard, disconnected from the code, and they rot there. Nobody remembers why new-checkout-v2 exists or whether it is safe to delete, so it sits at 100% for three years with a dead branch behind it. Experiment results end up in someone's old Slack thread and the same failed test gets re-run two years later.

Files also mean assignment can be a pure function. There is no assignment database and no network request to evaluate a flag, and a user never flips between variants across page loads or devices. The same math runs in the Rust CLI and the TypeScript SDK, locked by a shared test fixture that fails CI on both sides if the two implementations drift by a single bucket.