Code review is where quality happens — or doesn't. The right review tools make the difference between reviews that catch bugs and reviews that are just rubber stamps. Here's how GitHub, GitLab, Graphite, Reviewable, and others compare for real review workflows.
Quick Comparison
| GitHub PRs | GitLab MRs | Graphite | Reviewable | Gerrit | |
|---|---|---|---|---|---|
| Best for | Most teams (default) | GitLab users | Stacked PRs, fast-moving teams | Thorough, async reviews | Large-scale, strict reviews |
| Stacked diffs | No (sequential PRs) | No | Yes (core feature) | Yes (partial) | Yes (native) |
| AI review | Copilot PR review | GitLab Duo | In preview | No | No |
| Inline suggestions | Yes (commit suggestion) | Yes | Yes | Excellent | No |
| Review state tracking | Basic (requested, reviewed) | Good (approval rules) | Good | Excellent (per-file tracking) | Excellent (+1/+2 system) |
GitHub PR Reviews — The Default for Most Teams
GitHub's pull request review system is the most widely used. Copilot PR review (AI) summarizes changes and suggests improvements. The "suggest changes" feature lets reviewers propose exact code edits that the author can accept with one click. Branch protection rules enforce required reviewers, status checks, and signed commits.
Best for: Any team on GitHub. The default that works for 90% of teams.
Graphite — Stacked PRs, Faster Ships
Graphite solves the big PR problem: when your feature is 2,000 lines, nobody reviews it properly. Stacked PRs break large changes into small, sequential, independently reviewable chunks. Each PR is 100-300 lines and depends on the previous one. Reviewers can review incrementally instead of being hit with a mega-diff.
Best for: Fast-moving teams that ship continuously, projects where PRs regularly exceed 500 lines, teams that want smaller, faster reviews.
Reviewable — The Most Thorough Review Experience
Reviewable tracks review progress per file, per revision, per reviewer. It shows exactly which files have been reviewed, which comments are resolved, and which revisions addressed which feedback. For teams that take review seriously, Reviewable's thoroughness is unmatched.
Best for: Teams that treat code review as a critical quality gate, regulated industries, open source projects with many reviewers.
Decision Matrix
| Scenario | Best Tool |
|---|---|
| Standard team on GitHub | GitHub PRs |
| Large PRs, fast shipping, stacked diffs | Graphite |
| Most thorough, formal review process | Reviewable |
| On GitLab | GitLab MRs |
Bottom line: GitHub PRs for most teams. Graphite if your PRs routinely exceed 500 lines (it will change how you ship). Reviewable if your industry requires rigorous review. Good code review is a habit, not a tool — the tool just makes it easier. See also: GitHub vs GitLab vs Bitbucket and Git Workflows Guide.