Graphite vs Robin: Stacked PRs Meet Free AI Review

Graphite and Robin both put AI comments on your pull requests, but they’re built around different bets. Graphite is a hosted platform whose core idea is stacking — breaking big changes into small, sequenced PRs — with an AI reviewer layered on top. Robin is a single free, MIT-licensed GitHub Action that reviews PRs using whatever LLM endpoint you point it at, with no platform to adopt and no code leaving for a third-party service. If you want a workflow-changing platform and don’t mind hosted SaaS, Graphite is compelling. If you want review without changing your workflow or your data path, Robin is the leaner fit.

Key Takeaways

• Graphite is a hosted platform built around stacked PRs, with an AI reviewer (“Graphite Chat”) on top; it syncs deeply with GitHub.
• Robin is a free, MIT-licensed GitHub Action — no platform, no per-seat pricing, and your diff goes only to the endpoint you configure.
• Graphite changes how you author and sequence PRs; Robin changes nothing about your workflow except adding review comments.
• Pick Graphite for the stacking workflow and a polished hosted experience; pick Robin for zero cost, data control, and a two-command install.

What Is Graphite?

Graphite describes itself as “the AI code review platform where teams ship higher quality code, faster.” Its foundation is stacked diffs: rather than one large pull request, you break a change into a sequence of smaller, dependent PRs that are easier to review in order. On top of that workflow, Graphite adds AI review — including Graphite Chat, which it calls “the collaborative AI reviewer built into your PR page” — promising “high signal AI reviews on every PR to catch critical bugs.”

It’s a hosted SaaS product with deep GitHub sync, used by engineering teams at companies including Shopify, Ramp, and Asana. Graphite markets concrete productivity numbers from those customers — for example, it states Asana engineers “save 7 hours per week” and that Ramp “ships code 3x faster with Graphite.” (Those are Graphite’s own customer-reported figures, worth reading as vendor claims rather than independent benchmarks.) Pricing is freemium: “Free for your first 30 days. No credit card required,” then paid plans.

What Is Robin?

Robin is a free, MIT-licensed GitHub Action. You install it with one command, add three repository secrets (LLM_API_KEY, LLM_BASE_URL, LLM_MODEL), and every pull request from a branch with secret access gets an automatic review — a short summary plus inline comments on changed lines, the way a teammate would leave them. (Fork PRs from outside contributors don’t receive repository secrets, so those are triggered manually by a maintainer — a GitHub security boundary, not a Robin limitation.)

Run the installer from the root of the Git repository you want Robin to review:

npx robin-review

No npm? Install with curl instead:

curl -fsSL https://robinreview.dev/install.sh | bash

Both commands configure the Git repository you are currently in. The workflow and secrets are per repository; the companion agent skill is installed globally once per machine.

(Prefer to inspect before running? The same installer ships as a short shell script at robinreview.dev/script.)

The defining difference is where your code goes. Robin sends your diff directly from your GitHub Actions runner to the LLM endpoint you chose — OpenAI, Anthropic via a compatible proxy, a free model on OpenRouter, or a self-hosted model. There’s no Graphite-style platform in the middle receiving your code, no dashboard, and no per-seat bill. Comment /robin to re-review, /summary for a quick overview.

Stacking vs. Staying Put

The biggest practical difference isn’t the AI — it’s the workflow.

Graphite asks you to adopt stacking. For teams that buy into it, stacking genuinely speeds review: small sequenced PRs are easier to reason about than one sprawling diff, and Graphite’s tooling manages the dependencies between them. But it’s a real workflow change. Your team learns a new CLI and a new mental model for how changes are authored and merged. The AI review is one feature inside that larger platform commitment.

Robin asks you to adopt nothing. It rides on the GitHub flow you already use. You open PRs the way you always have; Robin just adds review comments. There’s no new authoring model, no CLI to learn beyond the install, and nothing for the rest of the team to change. The trade is that you don’t get stacking — if breaking large PRs into sequenced ones is the problem you’re trying to solve, Robin doesn’t address it. It only does review.

Data Routing and Cost

With Graphite, as with any hosted reviewer, your code passes through the vendor’s platform on its way to the underlying model. For teams comfortable with hosted SaaS that’s fine, and Graphite syncs tightly with GitHub to make it smooth. For teams with data-residency requirements, it’s a factor to weigh — the diff travels through a third party you must vet.

With Robin, the diff goes only to the endpoint you configure. No vendor sits in the path. On cost, the contrast is stark: Graphite is freemium with paid per-team plans after the trial; Robin is free, with your only spend being LLM tokens — which can be $0 on a free OpenRouter model. The need to control that cost is widespread — in Perforce’s 2025 State of Open Source report, the share of organizations naming cost savings as their top reason for choosing open source rose from 37% in 2024 to 53% in 2025.

Which Should You Choose?

Choose Graphite if stacked PRs sound like they’d fix a real pain on your team, you want a polished hosted platform with deep GitHub integration, and routing code through a vendor isn’t a blocker. The AI review comes as part of a broader, opinionated workflow that many teams genuinely like.

Choose Robin if you want AI review without changing how your team works, you need your code to stay on an endpoint you control, or cost is a hard constraint. In our experience maintaining Robin, the teams that pick it over a platform like Graphite usually aren’t rejecting stacking — they just don’t want to adopt a whole workflow platform to get review comments, and they want the data path to end at an endpoint they chose.

The two aren’t strictly mutually exclusive, either: a team could use Graphite for stacking and still value a free, data-local reviewer on repositories where the platform isn’t deployed.

Frequently Asked Questions

Is Graphite free?

Graphite is freemium. It offers a free 30-day trial with no credit card required, then moves to paid plans. Robin, by contrast, is fully free and MIT-licensed — your only cost is LLM token usage, which can be zero on a free model.

Do I have to use stacked PRs to use Graphite’s AI reviewer?

Stacking is Graphite’s core workflow and the main reason teams adopt it. You can use its review features without fully committing to stacking, but you’d be taking on a platform built around a workflow you’re not using. If you only want review comments on your existing GitHub flow, a standalone reviewer like Robin is a closer fit.

Does my code leave my infrastructure with either tool?

With Graphite, your code passes through Graphite’s hosted platform. With Robin, your diff goes only to the LLM endpoint you configure — there’s no intermediate service. If keeping code on an endpoint you control matters, that’s the deciding difference.

Where to Go From Here

If the stacking workflow is what you’re after, Graphite is worth a trial. If you want free, data-local AI review on the GitHub flow you already use, the Robin docs walk through the five-minute setup. For the broader field of reviewers — hosted, open-source, and self-hosted — the AI code review tools page maps the landscape, and the Robin vs CodeRabbit comparison covers another popular head-to-head in depth.