GitHub Copilot code review, CodeRabbit, and Greptile all comment on pull requests automatically, yet they bill in three incompatible ways: per AI credit, per seat with an hourly review cap, and per seat with a pool of review credits. Converting those into one comparable unit shows that the cheapest sticker price is not always the cheapest way to review a busy repository. This guide normalizes pricing, review limits, platform support, and stated weaknesses from each vendor's own pages.
This comparison is based on official documentation and pricing pages, verified as of 19 October 2026. It pairs with our Cursor, GitHub Copilot, and Claude Code pricing comparison, and with the security angle in Plugin4Shell and ZCode explained, since an automated reviewer is another agent with access to your repository.
Three billing models, side by side
| GitHub Copilot code review | CodeRabbit | Greptile | |
|---|---|---|---|
| Entry price | Copilot Business $19/seat/month; Pro $10/month | Essentials $24/user/month | Pro $30/seat/month; Starter free |
| What the price buys | Pooled AI credits (1,900 per Business user) | Per-user plan with a cap on reviews per developer per hour (5 on Essentials) | 50 review credits per seat per month |
| Cost per review | Estimated $0.05–$1 (Lite) or $0.25–$5 (Balanced, default) | Not stated per review; fair-usage cap per hour | 1 credit (base), 3 (Plus), 10 (Apex); extra credits $1 each |
| Platforms | GitHub | GitHub, GitLab, Bitbucket, Azure DevOps | GitHub, GitLab; also Bitbucket, Gitea, Perforce (Perforce on-premises only) |
| Self-hosting | Not applicable (GitHub-hosted) | Enterprise only, 500+ seats | Enterprise only |
| Free path | Free plan: limited "Review selection" in VS Code | An open-source plan is mentioned in an FAQ; its answer is not shown | Starter (50 credits, 1 developer); free for qualified open source |
A common yardstick: 100 reviews per developer per month
The three vendors do not publish a comparable "cost per review," so the following is a derived estimate, not a quote. It uses only the figures in the table above.
- Greptile (base reviews): $30 for the seat includes 50 credits. The next 50 base reviews cost $1 each, for roughly $80 in total.
- GitHub Copilot (Business): if one credit equals the $0.01 overage rate the documentation gives, 1,900 pooled credits cover about 19 to 380 Lite reviews, or about 4 to 76 Balanced reviews, depending on review size. A hundred Balanced reviews at the low end ($0.25) would be about $25 of credits, and at the high end ($5) about $500.
- CodeRabbit (Essentials): $24 flat, with a cap of 5 reviews per developer per hour. That ceiling is unlikely to bind at 100 reviews a month. The page adds only that "reviews beyond the included amount are available on consumption, with budget caps," without saying what the included amount is.
The takeaway: for small pull requests Copilot's credit model can be very cheap, for large ones it can exceed a seat price, and the per-seat tools trade that variance for a fixed monthly fee. Whichever you choose, your per-review cost depends on pull request size, which none of the pages let you predict precisely.
Where the vendors' own pages disagree or stay silent
- Copilot Free and code review. GitHub's plans page lists limited "Review selection" in VS Code for the Free plan, while the code review page states that Free users do not get a monthly allowance for code review. The two can both be true, but a reader skimming either alone would reach different conclusions.
- CodeRabbit's price period. The pricing page says annual plans "save 20%" without clearly stating whether $24, $48, and $72 are monthly or annual rates.
- CodeRabbit's platforms. The pricing page body does not list supported git platforms; they appear in the documentation instead (GitHub, GitLab, Bitbucket, Azure DevOps).
- Greptile's platforms. Its pricing page lists platforms only under Enterprise, so Starter and Pro platform support must be confirmed in the docs, where GitHub and GitLab are listed.
What each tool does not do
- Copilot code review warns it "is not guaranteed to spot all problems or issues in a pull request" and "sometimes it will make mistakes." You cannot switch its underlying model, some files such as package.json, logs, and SVGs are excluded, and it does not re-review after new pushes unless you configure that. If GitHub-hosted runners are disabled and no self-hosted runner exists, agentic features are unavailable.
- CodeRabbit reserves unit-test generation, finishing touches, and post-merge actions for the Team plan and above, and security features for Advanced. Self-hosting needs an Enterprise contract with 500 or more seats.
- Greptile says its comments become more relevant after "2-3 weeks" as it learns from reactions, which means early reviews may be noisier than later ones by the vendor's own account. Perforce support is on-premises only.
Setup and access: what you have to grant
Each tool needs repository access, and the documentation differs on how much effort that takes. CodeRabbit's platform guide says GitHub.com sets up its service account automatically, while other platforms may require you to create a dedicated service account, and you need ownership-level permissions for the organizations you connect. For private GitHub Enterprise Server or self-managed GitLab it offers a reverse-tunnel option that avoids opening inbound network access. Greptile says it builds a graph of the whole repository and posts findings in about three minutes. Copilot runs inside GitHub, but its agentic features rely on GitHub Actions runners, billed separately. Those differences matter most for security-sensitive teams.
Approval authority: the control that matters most
Copilot's documentation draws a line other pages in this space do not. By default its reviews do not count toward required approvals. When an administrator enables Copilot approvals (public preview), it can submit an approving review that satisfies a required-approval rule, and that approval is dismissed if new commits are pushed. Before turning that on, decide whether a model's sign-off should ever satisfy your branch protection rules. The CodeRabbit and Greptile pages read here do not describe equivalent merge-gating behavior, so confirm before assuming it.
Which one fits which situation
- Your code is on GitHub and you already pay for Copilot: Copilot code review adds no seat fee, but budget AI credits for large pull requests.
- You use GitLab, Bitbucket, or Azure DevOps: CodeRabbit lists all of them in its docs; Copilot is GitHub-only.
- You want a predictable cost per review: Greptile publishes explicit credit prices per review type ($1, $3, $10 on overage).
- You maintain a qualified open-source project: Greptile states free access for OSI-licensed non-commercial projects; Copilot offers free Pro to verified maintainers of popular open-source projects.
- You need self-hosting: only the Enterprise tiers of CodeRabbit and Greptile mention it.
Frequently asked questions
Does Copilot code review cost extra?
It is available on all paid Copilot plans and uses AI credits. GitHub's estimate is about $0.05 to $1 per review at Lite effort and $0.25 to $5 at the default Balanced effort.
Is there a free AI code review tool?
Greptile's Starter plan is free with 50 credits per month for one developer, and Copilot Free has a limited review feature in VS Code. CodeRabbit mentions an open-source plan, but the answer is not shown on the page read.
Can Copilot approve a pull request?
Only if an administrator enables Copilot approvals, a public-preview setting. By default its reviews do not count toward required approvals.
Which tool supports the most git platforms?
CodeRabbit's documentation lists GitHub, GitLab, Bitbucket, and Azure DevOps. Greptile lists GitHub and GitLab, plus Bitbucket, Gitea, and Perforce (Perforce on-premises only). Copilot code review runs on GitHub.
Last verified: 19 October 2026. Prices, credit rules, and plan features change often; confirm on each vendor's own page before buying.