Hey HN! We’re Oliver Gilan & Ben Warren and today we’re launching Mesa (https://mesa.dev) into public beta to help large engineering teams review code more effectively.

There are plenty of code review agents that exist but we found that they fall short in a number of ways. They don’t…

- Let you tailor the reviews with enough fidelity

- Give you control over the models used. If a new foundation model is released I might want to try it!

- Align the costs effectively

Mesa solves these problems with a multi-agent architecture where you define custom review agents that specialize in reviewing certain dimensions of your codebase. This allows you to finely control the review quality and receive reviews that are aware of specific dependencies, business logic, a specific domain in your codebase, or anything else you care about.

You can control the model a specialist uses which is great for trying newly released models but also for controlling costs. When a change is made to our database schema, we have a specialist agent that reviews it and uses the most expensive, smartest, model it can while our frontend agent uses a faster, cheaper agent.

Control over models and the fact that we only charge you for the tokens you use, at cost, aligns our cost structure and gives teams control that they do not get with other agents.

We’ve found code review to be a subtly big problem for teams trying to improve development velocity. It’s the primary point of contact for managing the changes to the living system of your codebase and mistakes are costly.

Missed bugs that make it to production can cause downtime, lost revenue, loss of trust, security breaches, compliance breaches, etc. Engineers spend hundreds of expensive man-hours that they do not enjoy reviewing code and still there’s too many mistakes being made.

We do not believe you can remove humans from the loop of reviews entirely but we can dramatically shift the amount of work done on an average code review and eliminate the need for human reviews altogether on a large subset of PRs. This sort of automation will lead to faster teams and more reliable codebases over time.

We are now in public beta and there’s a generous free tier (~100k lines reviewed free per month) available to all. Give it a spin and let us know what you think!

Oliver & Ben