OpenAI Built a New Git Backend That Cuts Push Latency Nearly 5x
Scaling Git at OpenAI
OpenAI's monorepo buckled under Codex-driven parallel work, with reliability dipping below 90%. So the team built Pando, a Git-compatible backend that scales writes across branches and reuses packfiles to serve reads. Pando now powers all OpenAI development, cutting median push latency nearly 5x and delivering nearly a petabyte of Git data daily. The post explains why they kept Git compatibility, compares Pando with 3PC and WAL-based designs, and outlines plans to upstream improvements.
We suffered slow fetches and pushes along with failed merges, with reliability at times falling below 90%.
- usrme
By my count, this OpenAI post is the fifth major article on the topic of scaling, with the previous four being:
- Cursor: https://cursor.com/blog/git-at-any-scale
- GitHub: https://github.blog/engineering/architecture-optimization/bu...
- Anthropic: https://www.anthropic.com/research/redesigning-source-contro...
- GitHub: https://github.blog/engineering/architecture-optimization/th...
Maybe also tangentially East River Source Control's too: https://ersc.io/blog/what-comes-after-git.
I'm wondering how much cross-pollination of ideas and subsequent implementation details there are between people working at these companies. It does seem like all of this could potentially converge.
- bigmadshoe
Can anyone explain to me what this massive volume of code could actually be doing? They obviously have variations of model architectures, training infrastructure, serving infrastructure, and the source for their apps.
Why would the volume that any of this be increasing exponentially? And what are all the engineers doing when (besides the model quality) their products don't seem to be changing very much?
- paxy
While I don't have any particular interest in the topic this is a great blog post. No AI in every second line, no needless marketing or hype. Just a bunch of engineers talking in their own voice about a topic in great detail with numbers, charts, visualizations.
- pksunkara
I don't see benchmarks anywhere in here. For example, how many pushes per second does this handle? And how many concurrent pushers? etc..
Disclaimer: I am building a code forge at https://juju.bi
- cadamsdotcom
> On handling a push, Pando validates the incoming packfile while streaming it to blob storage, without unpacking it into a local repository
Wasn't this flagged as a big risk, as it seems to place complete trust in the client?
Especially with all the rogue agents and containment/monitoring failures we have seen in 2026?
Would love to hear how the validation is deemed sufficient.
- japgolly
Interesting that they used both Lean and TLA+. I wish they'd speak more about that. I woulda thought they'd use one or the other. Generally speaking they both do the same thing (prove specs), but in very different ways.
- bob1029
Why not use a completely different VCS topology if you are a gigantic trillion dollar behemoth? Why are we still using the "distributed" git concept as the basis for everything?
Centralization is exactly what you want at this kind of scale. The most marginal participation from the server would make a huge difference.
There is a reason game studios don't use git. It's not just about the large objects.
- springtimesun
Is the increase in commits graph in percentages because it’s fewer than Anthropic’s rate? A case of commit envy?
In all seriousness though I have enjoyed reading these posts. I will never work at this scale, but I like to read how different teams approach problems like this and I do wonder if some of these approaches will trickle down (or up?) into regular practice as everyone is committing more and faster.