AI Code Review on GitLab Merge Requests: 2026 Guide

For AI code review on GitLab merge requests in 2026, start with GitLab Duo Code Review Flow if you want no new vendor: it costs one GitLab Credit for four reviews, about $0.25 a review at the listed $1 per credit. CodeRabbit, Greptile and Qodo cover GitLab.com with a token and a webhook, and PR-Agent is the open-source option that runs inside your own .gitlab-ci.yml. The right pick depends on whether you run GitLab.com or self-managed, and whether you want to pay per seat, per credit or per model token.

• GitLab Duo Code Review Flow: built in, agentic, billed in GitLab Credits, available on self-managed.
• CodeRabbit: the most detailed GitLab setup docs, GitLab.com and self-managed, free on public repositories.
• Greptile: codebase-aware review, GitLab.com on every plan, self-managed GitLab on Enterprise.
• Qodo: GitLab is a supported platform, with a credit-based Pro Team plan.
• PR-Agent: MIT licensed, runs as a GitLab CI job or a webhook server.
• repowise: deterministic merge request pipeline gates for GitLab, plus a GitHub PR bot.

Which AI code review tools work on GitLab merge requests?

Five options cover most teams, and they differ mainly in how they install and how they bill.

What does GitLab Duo Code Review do, and what does it cost?

GitLab Duo reviews a merge request in one of two ways, and which one runs depends on who requested the review. Per the GitLab docs, Code Review Flow is the agentic version: multi-step reasoning over repository structure and cross-file dependencies, with follow-up reviews. It needs no add-on and uses GitLab Credits. The older single-pass GitLab Duo Code Review sees only the merge request and its diffs and needs a GitLab Duo Enterprise seat. If the person who starts the review has an Enterprise seat, the single-pass version runs; group Owners can switch every review to the flow.

Availability is wide. The Code Review Flow page lists the Free, Premium and Ultimate tiers on GitLab.com, GitLab Self-Managed and GitLab Dedicated. It reached general availability in GitLab 18.8, and GitLab.com Free groups got it with credits in 18.10. You trigger it by assigning @GitLabDuo as a reviewer, mentioning it in a comment, or letting it start automatically when a merge request is created or marked ready.

For setup, a Developer role or higher, the group setting for foundational flows and Code Review, and a runner are required. The flow runs as a CI/CD job, so you either use GitLab hosted runners or configure runners with the gitlab--duo tag.

On price, the GitLab 18.10 release notes say a review "costs one GitLab Credit for four reviews, regardless of merge request size or complexity." The pricing page lists credits at $1 each, so a review works out to about $0.25, and Premium ($29 per user per month, billed annually) includes $12 of credits per user. That arithmetic is ours, not a GitLab figure. The pricing page does not list a Duo Enterprise price.

Pick it if you already pay for GitLab and want review inside the product, with no extra vendor to approve. It is the lowest-friction start on self-managed.

Does CodeRabbit work on GitLab, and how do you install it?

Yes. CodeRabbit supports both GitLab.com and self-managed GitLab. Plans on its pricing page are Essentials at $24 per developer per month billed annually ($30 monthly), Team at $48 and Advanced at $72, with Enterprise on custom pricing. Open-source public repositories get free reviews, and you are billed only for developers who open merge requests.

On GitLab.com, a GitLab admin creates a personal access token (api, read_api, read_user) for a dedicated service account, or a group access token on Premium or Ultimate, and adds it in CodeRabbit. You then install on repositories and CodeRabbit sets up the webhook (docs). Reviews appear under the service account's name.

For self-managed, the docs support GitLab 16.x and later, with an automated onboarding that uses a one-time admin token to create the bot user, or a manual route with an OAuth2 application. You enable merge request, comment and issue events on the webhook, and allow-list three CodeRabbit IP addresses if your instance filters traffic. Running CodeRabbit itself on your own infrastructure is an Enterprise option.

Pick it if you want the most documented GitLab setup and a polished general reviewer. See repowise vs CodeRabbit.

Does Greptile support GitLab?

Yes. Greptile reviews GitLab.com merge requests on every plan and self-managed GitLab on Enterprise. Its code providers page lists GitLab.com with an access token and webhook on all plans, and GitLab Self-Managed on the Enterprise plan. Greptile recommends a service account token, and your GitLab group must allow HTTP(S) git access.

Pricing from its pricing page: a free Starter plan for one active developer with 50 credits a month, Pro at $30 per seat per month with extra credits at $1 each, and Enterprise with self-hosting. A base review costs 1 credit, a plus review 3 and an apex review 10. A seat is any developer who received a review in the billing period. Open-source projects with an OSI-approved license can qualify for free use.

Pick it if you want review that reads the whole codebase and your team is comfortable with credit-based billing. See repowise vs Greptile.

What about Qodo and PR-Agent?

Qodo lists GitLab among its supported platforms, and its open-source PR-Agent is the most direct route to self-run review on GitLab. On its pricing page, Qodo lists GitLab alongside GitHub, Bitbucket and Azure. Pro Team is $30 with 2,500 credits, about 18 reviews a month, pooled across the team and designed for up to 30 users. There is no permanent free tier, only a 14-day trial and a program for qualified open-source projects. On-prem and air-gapped deployment are Enterprise only. The pages we read did not say whether self-managed GitLab is covered by the hosted product, so confirm that with Qodo.

PR-Agent is MIT licensed and lists GitLab as a supported provider. Per its GitLab guide, there are two modes:

• Pipeline mode: a job using the pragent/pr-agent:latest image runs describe, review and improve on merge request pipelines. It needs two masked CI/CD variables, a GitLab personal access token and your model key, and builds the GitLab URL from the CI server variables, so it works on self-managed.
• Webhook server: a Docker target you host, with push, comment and merge request events, which adds /review style comment commands.

The project describes itself as community-maintained and in the process of being donated to an open-source foundation, so check its release activity before you depend on it. You pay your model provider per token and nothing else.

Pick it if code must stay in your network and you are happy to own a small service or a pipeline job. See repowise vs Qodo.

What does repowise do for GitLab today?

repowise indexes GitLab.com projects on repowise.dev and runs open-source CI gates on merge request pipelines; the hosted PR review bot is a GitHub App. On GitHub, the bot posts one comment per pull request on public, private and organization repositories.

What ships for GitLab now:

• GitLab projects on repowise.dev. Connect GitLab.com under Settings, Git hosts, and add projects from any group or nested subgroup. repowise indexes each one and, with auto-sync on, updates it as you push (0.56.0 release note).
• A GitLab CI template. One include line in .gitlab-ci.yml adds a job per gate on merge request pipelines: patch coverage, doc drift, security and risk. Doc drift and security also write a GitLab Code Quality report, so findings show in the merge request's Code Quality widget (CI docs).
• No model, no account. The gates are plain commands that fail the pipeline on an exit code, so the same merge request gets the same result every time.
• GitLab-aware history. The open-source engine parses GitLab remotes including nested groups, reads merge request numbers from !N trailers, and recognizes GitLab CI build facts. A GitLab webhook can keep a self-hosted server's index current on push.

These gates are repeatable checks, not a reviewer that writes prose, so many GitLab teams pair them with one of the AI reviewers above: the gate decides if the merge request can land, the AI reviewer explains intent. For the trade-off, see deterministic vs LLM code review. On GitHub, the bot's costs are in AI code review pricing compared and best GitHub PR review bots.

Which one should you pick for GitLab?

Before choosing, work out cost at your volume. A team of 20 developers on CodeRabbit Essentials is $480 a month at the annual price. At GitLab Duo's rate of about $0.25 a review, that same $480 buys roughly 1,900 reviews, or about 96 per developer per month. Per-credit pricing favors moderate volume; per-seat pricing favors teams with heavy review volume.

How we checked

Every price and feature above comes from the vendor's own pricing page or docs, fetched on 15 October 2026. The best test is replaying about 20 of your own merged merge requests through a shortlist and keeping the tool whose comments you would have acted on.