Vivarium is a platform for reproducing bugs. Open a page, click once, and find out whether a previously-reported bug still reproduces — or whether a candidate fix actually fixes it.

For each upstream bug, the catalogue holds one recipe. Every recipe satisfies the same verdict.json v1 contract, so each page returns either reproduced (the bug reproduces) or unreproduced (it does not). Results show inline on the page and are also exposed as machine-readable JSON.

Vivarium ships bugs as runnable artefacts, not write-ups. Instead of someone telling you "this is a bug," you open it in your browser and watch.

The trigger was the surge of AI-generated bug reports and pull requests. Maintainers were drowning in plausible-but-unverified claims arriving at machine speed, and contributors had no way to check whether their own AI-drafted fixes actually worked. The shared root cause — no cheap, universal way to verify whether a bug is real or whether a fix actually fixes it — is what Vivarium addresses.

Bugs differ wildly in what environment they need. Vivarium organises reproduction techniques into three layers, and you don't pick the layer — the recipe declares it for you.

Vivarium has different entry points for different readers. The cards below are persona-route shortcuts — each one lands you at a "see it work yourself" surface within 5–30 minutes.