Catching Bugs Before They Land: JiTTesting’s Human-on-the-Loop Approach at Full Scale
Meta has deployed LLM-generated executable tests into production infrastructure to catch bugs pre-merge.
“Catching JiTTests are no longer a research prototype; they're part of Meta's infrastructure, and they're helping our engineers catch more bugs with less load and a smaller chance of false positives.”
Meta has moved its LLM-powered Just-in-Time Test (JiTTest) system from research prototype to production infrastructure, deploying it across its hundreds-of-millions-lines codebase. Unlike conventional LLM code review, Catching JiTTests generates executable tests that concretely demonstrate behavioral regressions introduced by a diff. The production deployment demonstrates that LLM-assisted testing at hyperscale is viable, a meaningful signal for teams evaluating AI in their own software delivery pipelines.