AI Code Review Tools in 2026: 5 Options Compared (Free Included)

Posted on Oct 20 • Originally published at aistacklab2026.blogspot.com

AI code review went from demo joke to default pull-request infrastructure in about two years, and in 2026 the interesting question is no longer whether a bot should read your diff — it's which bot, and what it costs when the free tier ends. I read five vendors' own pricing pages on October 19, 2026 — every number below comes from those pages, not from memory or a stale listicle.

Public repositories: CodeRabbit is the strongest free option — reviews free forever on public repos, paid plan $24/dev/month billed annually. Private repos, zero budget: Greptile's free plan (50 credits/month, one developer, unlimited repos) or Sourcery's free plan. Already paying for GitHub Copilot Pro at $10/month? Its native code review is the cheapest upgrade you'll never see on a separate bill. For teams, per-seat math matters more than any individual feature — these tools differ far more in pricing model than in review quality.

Three different products wear the same label, and mixing them up is how people get disappointed with the category:

All three styles catch bugs; they differ in how much they intrude and where your code goes while they think.

Copilot's code review runs on github.com on any pull request, including from users who don't pay for Copilot — if the organization allows it. The plans page is specific: Copilot Free is $0 but limited to 2,000 completions and 50 chat requests/month and does not include code review; review starts at Pro, $10/month (also in Pro+ $39 and Max $100). Two fine-print details that matter: code review consumes AI Credits and Actions minutes, so heavy use is metered even on a paid plan — and an org admin can enable Copilot code review for members without a Copilot license, billed to the organization. That makes Copilot a legitimate team-wide review layer without buying everyone a seat, if someone watches the Actions bill.

The most established dedicated review bot, and its pricing page states the deal plainly: free reviews forever for public repositories. Private repos move to Essentials — the page notes it keeps the former Pro price of $30/developer/month, or $24 billed annually. That's the most expensive paid option here, which funds the free open-source tier. It reviews diffs line by line, learns your codebase conventions over time, and answers questions in the PR thread. If you maintain open-source projects, there's no rational reason not to have it installed.

Qodo (whose merge agent grew out of PR-Agent) has the most honest pricing page in the category: no permanent free tier for private repos, and it says so. You get a 14-day trial with no credit card, then credit-based plans — the trial tiers on the page list roughly 18 reviews/month at 2,500 credits and about 36 at 5,000 — plus a free plan for open-source projects through Qodo for Open Source. The differentiator is generated tests: it reviews your PR and writes the unit tests the diff implies. Choose it if test coverage is the actual hole in your workflow; skip it if you wanted a permanently free private-repo bot, because this one isn't pretending to be that.

Greptile's Starter plan is the most generous genuinely-free private-repo option here: free, 50 credits/month, one active developer, unlimited repositories, plus a free tier for qualified open-source projects. Paid Pro is $30/seat/month with extra credits at $1 each. Fix the word credits in your head — each review action consumes them, so 50 credits is a light cadence: roughly a review a day, not a review a minute. The pitch is codebase-aware review that reads your whole repository for context, not just the diff. For a solo dev pushing a few PRs a week to private repos, the free tier is genuinely enough; for a busy team, the credits meter is where bill shock lives.

Sourcery started as a Python refactoring linter and evolved into a GitHub/GitLab review tool with a two-minute install and a free plan that stays free. Open-source projects are free outright; paid tiers are the second-cheapest here — Pro $12/seat/month, Team $24, both billed annually. The most opinionated of the five: it enforces consistent style and flags constructs it considers risky, which makes it the best fit for teams that keep arguing about the same patterns in review comments. Don't expect architecture-level commentary; expect your future self to stop writing the same loop badly.

From my own workflow: when one of these bots flags a diff and I want an agent to actually act on it — run the suite, apply the fix — I dispatch from the terminal with AgentDelegator CLI, the small tool we build and use daily. $5 one-time (price re-verified on Gumroad, October 19, 2026). It is not a code reviewer; it's the dispatch layer between a review comment and a running agent: AgentDelegator CLI on Gumroad.

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Read the table as a ladder. Zero dollars gets you: public-repo reviews (CodeRabbit, Sourcery, Sonar's open-source offering, Greptile's qualified OSS tier), a light private-repo cadence (Greptile's 50 credits, Sourcery's free plan), or Copilot's completions and chat — but not its reviews. The first real payment in this category is either $10 (Copilot Pro, if review is the point) or nothing at all if your repos are public. The trap isn't the sticker price; it's metering. Credits-per-review pricing (Qodo, Greptile) and credits-plus-Actions-minutes pricing (Copilot) both convert a busy sprint into an unpredictable invoice. Per-seat pricing (CodeRabbit, Sourcery) is boring and predictable, which is a feature.

Two honorable mentions outside the five: Sonar's Gitar AI Code Review is free forever for public, open-source-licensed repos with feature parity to the paid team plan (and SonarQube's team plan is free for private projects up to 50,000 lines) — if your stack is already Sonar-based, start there. Graphite also has a free hobby tier for personal repos.

Honesty section: every number was read from the vendors' own pricing pages on October 19, 2026 — and re-read, not remembered. What was NOT done: no controlled benchmark trials, no accuracy scoring against a labeled bug dataset, because nobody publishes one. The honest claim is narrower: this desk runs several of these tools daily on its own code. Find a number that drifted? Corrections welcome in the comments and we'll re-fetch and fix it the same day.

For public repositories the answer is almost boring: install CodeRabbit (free forever) and Sourcery (free plan) and keep the one whose comments you actually read — two free bots reviewing one PR is a reasonable configuration. For private repositories with zero budget, Greptile's 50 free credits/month is the only serious private-repo tier in this list, with Sourcery's free plan as the style-focused second pair of eyes. For developers already paying for Copilot Pro, native code review is included — there's nothing else to buy. And for teams: buy the predictable per-seat tool, not the credits tool, unless your sprint volume is genuinely low. In 2026, AI review is table stakes, the free tiers are real, and the only expensive mistake is a credits meter running loose on a busy repository.

Worth a read next on the blog: 10 best AI coding tools in 2026, tested — the wider category these review bots live in.