Best tools for Code Review

LSP-based AI code review agent backed by Y Combinator

mrge is a YC-backed AI code review agent that uses Language Server Protocol analysis to provide deep, context-aware pull request reviews. It goes beyond surface-level pattern matching by understanding project structure, type information, and cross-file dependencies. Integrates with GitHub and GitLab to deliver automated reviews that catch logic errors, security issues, and architectural inconsistencies.

AI coding agent by JetBrains for autonomous task execution

Junie is JetBrains' AI coding agent that handles engineering tasks autonomously within JetBrains IDEs and from the terminal. It plans multi-step workflows, executes code changes, runs tests, and verifies results using full project context. Supports BYOK with Anthropic, OpenAI, Google, and others. Achieves 60.8% on SWE-bench Verified. Available as IDE plugin and CLI.

Blazing-fast PHP linter, formatter, and static analyzer in Rust

Mago is a comprehensive PHP toolchain written in Rust that unifies linting, formatting, and static analysis into a single binary. It enforces PER-CS formatting standards, catches code smells with 100+ lint rules, and performs deep type inference for semantic analysis. Inspired by Clippy and OXC from the Rust ecosystem, it delivers performance orders of magnitude faster than PHPStan and Psalm while requiring no PHP runtime to execute.

CLI tool to convert codebases into LLM-ready prompts

code2prompt is a Rust CLI that converts entire codebases into structured prompts optimized for LLM context windows. It intelligently filters files using gitignore patterns, respects token budgets, generates directory tree visualizations, and supports custom Handlebars templates for output formatting. The tool addresses the core challenge of feeding large codebases to AI coding assistants by producing clean, organized context that maximizes the value of limited token budgets.

Git-native AI agent session capture and reasoning traceability

Checkpoints by Entire captures the full reasoning context behind AI-generated code directly in Git. Founded by former GitHub CEO Thomas Dohmke with a 60 million dollar seed round, it records transcripts, prompts, files touched, token usage, and tool calls alongside every commit. Session metadata lives on a separate branch keeping your history clean, with rewind capabilities to restore any previous agent checkpoint when things go sideways.

Agent harness performance system with 30+ agents and 136 skills

Everything Claude Code is a comprehensive agent harness performance optimization system providing 30 specialized agents, 136 skills, 60 commands, and automated hook workflows for AI-assisted development. Born from an Anthropic hackathon winner and evolved over 10+ months of intensive daily use, it works across Claude Code, Codex, Cursor, and OpenCode with built-in security scanning via AgentShield, continuous learning, and research-first development patterns.

Virtual engineering team as Claude Code skills by YC CEO Garry Tan

GStack transforms Claude Code into a structured virtual engineering team through 23 opinionated slash command skills created by Y Combinator CEO Garry Tan. It assigns specialist roles including CEO product review, engineering manager architecture oversight, designer visual audit, QA lead with real browser testing, and release engineer deployment. Each skill enforces focused workflows with clear decision principles for running parallel coding sessions.

Human-in-the-loop approval and oversight layer for AI coding agents

HumanLayer is a YC-backed platform that adds human approval, oversight, and escalation workflows to AI coding agents. Instead of letting agents execute autonomously, HumanLayer provides checkpoints where humans review and approve agent actions before they touch real codebases and infrastructure. It bridges the gap between autonomous AI coding and enterprise-safe deployment by making human oversight programmable.

Find unused files, dependencies, and exports in JavaScript and TypeScript projects

Knip is an open-source CLI tool that detects unused files, dependencies, devDependencies, and exports in JavaScript and TypeScript codebases. It analyzes the full dependency graph to identify dead code that accumulates over time — especially relevant for AI-generated codebases where unused artifacts pile up faster than manual cleanup can handle. With over 10,800 GitHub stars, it has become a standard code hygiene tool in the JS/TS ecosystem.

Incremental parsing system powering code intelligence in AI editors

Tree-sitter is an incremental parsing library with 19,000+ GitHub stars used by Cursor, Neovim, GitHub, and Helix for real-time syntax analysis. It generates concrete syntax trees that update incrementally as code changes, enabling AI code editors to understand program structure for intelligent completions, refactoring, and code navigation.

Static linter that catches production bugs in AI-generated code

prodlint is a zero-config static analysis tool with 52 rules targeting production bugs that AI coding tools consistently produce. It catches hallucinated npm imports, missing authentication checks, Prisma writes outside transactions, exposed secrets via NEXT_PUBLIC prefixes, and other patterns specific to code generated by Cursor, Claude Code, Bolt, and v0. Runs in one second via npx with no configuration needed.

Most popular VS Code Git extension with 30M+ installs

GitLens is the most-installed Git extension for VS Code with over 30 million installs. It supercharges Git inside the editor with inline blame annotations, rich commit history visualization, file and line history, AI-powered commit summaries, and interactive rebase tools. Pro features include GitKraken-powered team analytics and visual diff tools. Maintained by GitKraken.

Google's enterprise AI coding assistant powered by Gemini

Gemini Code Assist is Google's AI-powered coding assistant that integrates into VS Code, JetBrains IDEs, and GitHub workflows. Powered by Gemini models with a large context window, it provides code completion, generation, transformation, and explanation across Java, Python, Go, TypeScript, and more. Features enterprise code customization with private codebases and Google Cloud integration for cloud-native development.

Rust-powered JavaScript linter that is 50-100x faster than ESLint

Oxlint is an extremely fast JavaScript and TypeScript linter built as part of the OXC (Oxidation Compiler) toolchain written in Rust. It runs 50-100x faster than ESLint by parsing and analyzing code in a single optimized pass without requiring any plugins or configurations. Oxlint ships with 520+ built-in rules covering correctness, performance, and style checks, and is designed to run alongside ESLint during migration. Part of Evan You's VoidZero initiative, OXC has over 20,000 GitHub stars.

Extremely fast Python linter and formatter written in Rust

Ruff is a Python linter and code formatter written in Rust by Astral that runs 10-100x faster than existing tools like flake8, isort, and Black. It implements over 800 lint rules from dozens of popular plugins in a single binary, handles auto-fixing for most violations, and includes a built-in formatter compatible with Black. Adopted by FastAPI, Hugging Face, Pandas, and Apache Airflow, Ruff has over 38,000 GitHub stars and processes entire codebases in milliseconds.

Developer productivity platform with merge queues and flaky test detection

Aviator is a developer productivity platform combining merge queues, stacked PRs, automated code review, and flaky test management. Its merge queue prevents broken main branches by testing PRs in order before merging. Flaky test detection identifies unreliable tests causing CI failures. Founded by ex-Google engineers who built internal developer tools at scale. YC-backed with $2.3M seed from Elad Gil. Used by Bosch, Benchling, and Lightspeed.

Pack your entire codebase into a single AI-friendly file

Repomix packages entire repositories into single AI-optimized files for feeding to LLMs like Claude, ChatGPT, and Gemini. It outputs XML, Markdown, JSON, or plain text with token counting, security scanning via Secretlint, and Tree-sitter-based code compression. Works as CLI, MCP server, or Chrome extension for GitHub. Supports Claude Agent Skills generation. 37,500+ uses on AIBase, MIT licensed, with a web interface at repomix.com for zero-install usage.

AI-native Git client with virtual branches and smart commits

GitButler is an open-source Git client that reimagines version control with virtual branches, AI-assisted commit organization, and intelligent conflict resolution. Co-founded by Scott Chacon (Git co-creator and former GitHub CTO), it lets developers work on multiple changes simultaneously without traditional branch overhead. The AI suggests branch groupings, splits commits semantically, and guides merge conflicts. 14,200+ GitHub stars, dual-licensed GPL/Commercial.

AI-powered pull request summaries and code review

WhatTheDiff is an AI tool that generates human-readable pull request summaries and suggests code improvements. It analyzes code diffs to explain what changed and why in plain language, helping reviewers understand PRs faster. Integrates with GitHub and supports automated refactoring suggestions through a /wtd command. Useful for teams wanting to improve PR review speed and maintain changelog quality.

Google's proactive coding agent for async repository maintenance

Jules is Google's coding agent that proactively scans repositories for TODO comments, bug patterns, and improvement opportunities, proposing code changes without explicit user requests. Built on Gemini models, it operates asynchronously in the background, completing over 140,000 code improvements. Handles routine maintenance tasks like dependency updates, code cleanup, and follow-on work from completed features.

Context-aware AI review with business logic validation

Umaku is a context-aware AI code review agent that understands full codebase and business logic context, detecting inconsistencies and assessing quality and risk beyond syntax-level analysis. It auto-generates and validates QA test cases from reviewed code, making it particularly effective for reviewing AI-generated code where product-intent validation matters more than style checking.

Pull Requests as a Service with AI + developers

GitStart is a YC-backed platform that delivers merge-ready pull requests by combining AI coding agents with human developer oversight. Teams assign sprint-sized tickets and the AI Ticket Studio converts vague requirements into well-scoped specs, then hybrid agents generate production-ready code through a five-stage quality process with a 98% merge rate reported across customer teams.

Code health analysis and technical debt quality gates

CodeScene analyzes code health, technical debt, and delivery risks by examining code patterns and change frequency, then integrates as CI/CD quality gates on pull requests. It scales AI-assisted development safely by measuring whether generated code maintains architectural integrity, with on-premises deployment options and pricing that starts free for open-source projects.

AWS managed AI code review for Java and Python

Amazon CodeGuru Reviewer is an AWS managed service that provides automated code analysis and recommendations on pull requests for Java and Python codebases. It integrates with GitHub, Bitbucket, and AWS CodeCommit, using machine learning trained on Amazon's internal code review practices to identify bugs, security vulnerabilities, and performance issues with IAM-based access control for enterprise governance.