Cubic is a Y Combinator-backed AI code review platform that positions itself as the review tool for the AI coding era. Priced at $30 per developer per month with unlimited reviews, Cubic integrates with GitHub as a one-click app and is free for public repositories. The platform onboards by reading your senior developers' existing PR comment history to understand your team's review patterns and standards. Cubic is used in production by teams at cal.com, n8n, and PostHog, and users on Product Hunt describe it as catching complex issues with the right balance between signal and noise. The platform supports all major programming languages and is SOC 2 compliant.
Greptile takes the deepest approach to codebase understanding among AI code review tools. Before reviewing any code, it indexes every function, class, and dependency in your repository to build a complete code graph. This enables Greptile to catch bugs that only manifest through cross-file interactions, a class of issues that diff-based tools inherently miss. Independent benchmarks show an 82% bug catch rate, and the v4 release in March 2026 increased addressed comments per PR by 74% while reducing false positives. Greptile costs $30 per developer per month and is backed by Y Combinator with a $180 million valuation after its Benchmark-led Series A.
Graphite takes a different path by combining stacked pull requests with AI-powered code review through its Graphite Agent. The stacked PR workflow breaks large changes into small, dependent PRs that merge in sequence, which fundamentally changes the review surface area. Graphite Agent maintains an unhelpful comment rate under 3%, and when it flags an issue, developers change the code 55% of the time compared to 49% for human reviewers. Shopify reported 33% more PRs merged per developer after adoption, and Asana saw engineers save 7 hours weekly with 21% more code shipped. The constraint is that Graphite is GitHub-only and requires the entire team to adopt stacked workflows.
The core architectural difference lies in how each tool understands code changes. Cubic uses a micro-agent architecture where thousands of specialized agents continuously scan the entire codebase, catching issues beyond just PR diffs. It groups related changes together and orders them logically rather than alphabetically, helping reviewers understand complex PRs. Greptile builds a dependency graph and traces how changes propagate across files. Graphite Agent benefits from the stacked PR structure, where each small PR is inherently easier to reason about, reducing the need for deep cross-file analysis.
False positive management is a critical differentiator. Greptile's deep analysis produces the highest catch rate but also generates more false positives, with benchmark testing showing 11 false positives compared to CodeRabbit's 2 in head-to-head evaluation. Cubic claims fewer false positives than the industry average through its reasoning logs and micro-agent architecture, with transparency into why each issue was flagged. Graphite Agent's under 3% unhelpful comment rate suggests the tightest precision, though this may partly reflect the simpler review surface created by stacking PRs into smaller chunks.