TREX: An AI code reviewer that runs your code

Static code review has a hard ceiling — it reads code but can't catch runtime bugs like race conditions or UI regressions. Greptile built TREX, an execution layer that spins up sandboxed environments, runs actual code, and captures screenshots, logs, and API traces as verifiable artifacts. The orchestrator agent delegates to parallel subagents, each inheriting shared context to avoid redundant work.