OpenAI says it built a Git backend called Pando because Codex pushed its monorepo past what its old source-control setup could serve

OpenAI says that around the end of last year its monorepo systems began struggling, with slow fetches and pushes, failed merges and reliability at times below 90%. Its explanation is that Codex lets each engineer have several changes ready for CI at once, and each push can start several jobs fetching the same commit. Pando, which the post says now powers all development in the monorepo, updates each branch independently and reuses packfiles across fetches. OpenAI reports that it cut median push latency by nearly 5x and now serves nearly a petabyte of Git data per day. It says Pando stays compatible with the Git protocol and client, and that the tradeoff is that a reader looking at several branches can see them at different points in time.

These are OpenAI's own figures about an internal system we cannot inspect. We read the post through its comparison of existing replicated-Git designs and not the sections after it.

Why it matters: The post is a first-party account of where agent-driven volume showed up in infrastructure: concurrent pushes to many branches and many readers fetching the same history. If your agents open more branches and CI runs than your people did, the shared source-control and CI path is a place to measure.