Best Free Code Quality Tools of 2026

Aikido Security

Ship quality code, faster. Aikido built AI-native code quality, with instant feedback, smart detection, and clear auto-generated PR comments, so you can focus on building.

128 Ratings

Starting Price: Free

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Codespy AI Detector is a powerful tool designed to identify AI-generated code within software projects quickly and accurately. It supports popular programming languages such as Java, Python, JavaScript, C++, C#, and PHP. The platform helps developers find AI-written code from models like ChatGPT, Gemini, and Claude, which can introduce bugs or unexpected errors. Codespy integrates seamlessly with common development environments like Visual Studio Code and is available as a ChatGPT plugin. Its technology enables teams to create processes and guardrails around AI code usage to reduce risk and improve code quality. With simple pricing plans and no credit card required for the free tier, Codespy is accessible to individuals and businesses of all sizes.

2 Ratings

Starting Price: $27.98/month

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ThinkReview

ThinkReview is an AI-powered code-review tool built for developers using GitLab and Azure DevOps that delivers instant analysis of merge requests and pull requests directly in the browser. Without requiring complex setup or configuration, it detects when you are viewing a MR/PR, fetches the code changes, and displays an AI-generated review panel that includes summaries, security findings, quality suggestions, and auto-generated review comments. Users can engage in chat-style interaction with the changes, ask questions, regenerate review perspectives, and receive smart follow-up questions for discussion. It supports both self-hosted and cloud instances, works out of the box, and is available as a browser extension containing features such as automatic detection of MRs/PRs, smart summaries, comment generation, and multilingual support. Built for speed and ease, ThinkReview focuses on improving code quality and accelerating review cycles by embedding AI into existing workflows.

1 Rating

Starting Price: $6.99 per month

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Rollbar

Discover, predict, and resolve errors in real-time. Go beyond crash reporting, error tracking, logging and error monitoring. Get instant and accurate alerts — plus a real-time feed — of all errors, including unhandled exceptions. Our automation-grade grouping uses machine learning to reduce noise and gives you error signals you can trust.

Starting Price: $19.00/month

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Codecov

Develop healthier code. Improve your code review workflow and quality. Codecov provides highly integrated tools to group, merge, archive, and compare coverage reports. Free for open source. Plans starting at $10/user per month. Ruby, Python, C++, Javascript, and more. Plug and play into any CI product and workflow. No setup required. Automatic report merging for all CI and languages into a single report. Get custom statuses on any group of coverage metrics. Review coverage reports by project, folder and type test (unit tests vs integration tests). Detailed report commented directly into your pull request. Codecov is SOC 2 Type II certified, which means a third-party audits and attests to our practices to secure our systems and your data.

Starting Price: $10 per user per month

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Stickler CI

Stickler

Align your team's code reviews with automatic style feedback, for all the languages you use, all in one place. Connecting your repository is a couple of clicks away and our reviews finish in record time. Use the default style guides or customize each tool to fit your team's tastes. Use auto fixing to correct your team's style errors so you can focus on feedback. Stickler CI only keeps your code on our servers for the duration of a review. After the comments for a review are posted your code is removed from our servers. Incrementally improve and standardize the quality of your code in each pull request. Ensure your coding standards are applied consistently as code changes without having to disrupt your team. Make sure your code quality and style are standardized by automatically applying style and quality checking tools. Either use the defaults or customize linters to fit your existing coding standards.

Starting Price: $15 per month

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Devel::Cover

metacpan

This module provides code coverage metrics for Perl. Code coverage metrics describe how thoroughly tests exercise code. By using Devel::Cover you can discover areas of code not exercised by your tests and determine which tests to create to increase coverage. Code coverage can be considered an indirect measure of quality. Devel::Cover is now quite stable and provides many of the features to be expected in a useful coverage tool. Statement, branch, condition, subroutine, and pod coverage information is reported. Statement and subroutine coverage data should be accurate. Branch and condition coverage data should be mostly accurate too, although not always what one might initially expect. Pod coverage comes from Pod::Coverage. If Pod::Coverage::CountParents is available it will be used instead.

Starting Price: Free

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Tarpaulin

Tarpaulin is a code coverage reporting tool for the cargo build system, named for a waterproof cloth used to cover cargo on a ship. Currently, tarpaulin provides working line coverage and while fairly reliable may still contain minor inaccuracies in the results. A lot of work has been done to get it working on a wide range of projects, but often unique combinations of packages and build features can cause issues so please report anything you find that's wrong. Also, check out our roadmap for planned features. On Linux Tarpaulin's default tracing backend is still Ptrace and will only work on x86 and x64 processors. This can be changed to the llvm coverage instrumentation with engine llvm, for Mac and Windows this is the default collection method. It can also be run in Docker, which is useful for when you don't use Linux but want to run it locally.

Starting Price: Free

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coverage

pub.dev

Coverage provides coverage data collection, manipulation, and formatting for Dart. Collect_coverage collects coverage JSON from the Dart VM Service. format_coverage formats JSON coverage data into either LCOV or pretty-printed format.

Starting Price: Free

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Slather

Generate test coverage reports for Xcode projects & hook it into CI. Enable test coverage by ticking the "Gather coverage data" checkbox when editing a scheme.

Starting Price: Free

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NCover

NCover Desktop is a Windows application that helps you collect code coverage statistics for .NET applications and services. After coverage is collected, Desktop displays charts and coverage metrics in a browser-based GUI that allows you to drill all the way down to your individual lines of source code. Desktop also allows you the option to install a Visual Studio extension called Bolt. Bolt offers built-in code coverage that displays unit test results, timings, branch visualization and source code highlighting right in the Visual Studio IDE. NCover Desktop is a major leap forward in the ease and flexibility of code coverage tools. Code coverage, gathered while testing your .NET code, shows the NCover user what code was exercised during the test and gives a specific measurement of unit test coverage. By tracking these statistics over time, you gain a concrete measurement of code quality during the development cycle.

Starting Price: Free

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JaCoCo

EclEmma

JaCoCo is a free code coverage library for Java, which has been created by the EclEmma team based on the lessons learned from using and integrating existing libraries for many years. The master branch of JaCoCo is automatically built and published. Due to the test-driven development approach, every build is considered fully functional. See the change history for the latest features and bug fixes. SonarQube code quality metrics of the current JaCoCo implementation are available on SonarCloud.io. Integrate JaCoCo technology with your tools. Use JaCoCo tools out of the box. Improve the implementation and add new features. There are several open-source coverage technologies for Java available. While implementing the Eclipse plug-in EclEmma the observation was that none of them are really designed for integration. Most of them are specifically fit to a particular tool (Ant tasks, command line, IDE plug-in) and do not offer a documented API that allows embedding in different contexts.

Starting Price: Free

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AppMap

Runtime code reviews for every code change in the code editor and in CI. Catch runtime performance, security, and stability problems while you code, before they hit production. Collaborate on a team member’s application behavior problem without having to replicate their environment. Automate AppMap generation in CI, get alerts for performance and security flaws, and compare observability and alerts across branches and teams. Run AppMap in CI to automate observability, create OpenAPI docs, and much more. AppMap code reviews link to rich resources that enable you to uncover the root causes of unexpected behavior. Sequence diagrams diffs vividly showcase behavioral changes in your code.

Starting Price: $15 per user per month

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PullRequest

HackerOne

Get on-demand code reviews from vetted, expert engineers enhanced by AI. Add senior engineers to your team every time you open a pull request. Ship better, more secure code faster with AI-assisted code reviews. Whether you're a development team of 5 or 5,000, PullRequest will supercharge your existing code review process and adapt to your needs. Our reviewers will help your team catch security vulnerabilities, find hidden bugs, and fix performance issues before they reach production. All of this is done within your existing tools. Expert human reviewers enhanced by an AI analysis to pinpoint high-risk security hotspots. Intelligent static analysis combining open source tools and proprietary AI shown to reviewers for deeper insights. Save your senior staff some time. Make meaningful progress resolving issues and improving code while other members of your team are busy building.

Starting Price: $129 per month

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GitChat

Improve your code and catch bugs faster with AI-generated summaries and real-time chat. Get instant context with AI summaries on every pull request, helping your team save time on code reviews. Enhance code quality and ship faster with instant, actionable feedback on every pull request. Use GitHub Pull Request Comments to chat with AI to uncover issues and get instant feedback on your code. Customize your code review assistant by setting up rules and filters to meet your team's needs and get optimal results. Supercharge your code reviews with GitChat. Improve your code quality and ship products faster.

Starting Price: Free

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Early

EarlyAI

Early is an AI-driven tool designed to automate the generation and maintenance of unit tests, enhancing code quality and accelerating development processes. By integrating with Visual Studio Code (VSCode), Early enables developers to produce verified and validated unit tests directly from their codebase, covering a wide range of scenarios, including happy paths and edge cases. This approach not only increases code coverage but also helps identify potential issues early in the development cycle. Early supports TypeScript, JavaScript, and Python languages, and is compatible with testing frameworks such as Jest and Mocha. The tool offers a seamless experience by allowing users to quickly access and refine generated tests to meet specific requirements. By automating the testing process, Early aims to reduce the impact of bugs, prevent code regressions, and boost development velocity, ultimately leading to the release of higher-quality software products.

Starting Price: $19 per month

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Dependabot

GitHub

Dependabot is an automated dependency management tool that integrates seamlessly with GitHub repositories to keep project dependencies up-to-date and secure. By regularly scanning for outdated or vulnerable libraries, Dependabot proactively generates pull requests to update these dependencies, ensuring that projects remain secure and compatible with the latest releases. Its core logic is designed to handle various package managers and ecosystems, making it versatile for diverse development environments. Developers can customize Dependabot's behavior through configuration files, allowing for tailored update schedules and specific dependency rules. By automating the dependency update process, Dependabot reduces the manual effort required to maintain project dependencies, thereby enhancing overall code quality and security.

Starting Price: Free

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Patched

Patched is a managed service that leverages the open-source framework Patchwork to automate development tasks such as code reviews, bug fixing, security patching, and documentation. By utilizing large language models, Patched enables developers to build and deploy AI-assisted workflow, referred to as "patch flows", that autonomously handle post-code activities, thereby enhancing code quality and accelerating development cycles. The platform offers a user-friendly graphical interface and a visual workflow builder, allowing for the customization of patch flows without the need to manage infrastructure or LLM endpoints. For those who prefer self-hosting, Patchwork provides a self-hosted command-line interface agent that integrates seamlessly with existing development pipelines. Patched emphasizes privacy and control, enabling deployment within an organization's infrastructure using its own LLM API keys.

Starting Price: $99 per month

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PHPStan

PHPStan is an open source static analysis tool for PHP that identifies bugs in your codebase without the need for writing tests. It thoroughly scans your entire code, detecting both obvious and subtle issues, including those in rarely executed conditional statements that tests might not cover. By integrating PHPStan into your development environment and continuous integration pipelines, you can prevent bugs from reaching production. It is compatible with legacy codebases, even those lacking an autoloader, and facilitates gradual improvement through configurable rule levels. This approach allows developers to incrementally enhance code quality without being overwhelmed by numerous errors on the initial run. PHPStan supports advanced PHP features ahead of their official release, such as generics, array shapes, and checked exceptions, by leveraging PHPDocs. It also offers extensions for popular frameworks like Symfony, Laravel, and Doctrine, ensuring comprehensive understanding.

Starting Price: Free

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Fynix

Fynix is an AI-powered platform designed to boost software development productivity through intelligent coding assistance and agent-based code reviews. It integrates directly into popular IDEs like VS Code and offers features such as context-aware autocomplete, natural language commands for code fixes and translations, and automatic code flow visualizations. Fynix’s Code Assistant helps developers write cleaner, more efficient code faster, while its upcoming Code Quality Agent will automate bug detection and enforce coding standards. With support for multiple programming languages and frameworks, and integrations with tools like Jira, Fynix is a versatile platform for improving coding efficiency and collaboration.

Starting Price: Free

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Diamond

Diamond is an advanced AI code review tool that provides immediate, actionable feedback on every pull request, enhancing code quality and accelerating development cycles. It automatically identifies potential issues such as logic bugs, security vulnerabilities, performance bottlenecks, and documentation inconsistencies, allowing teams to focus more on building and less on manual reviews. With zero setups required, Diamond integrates seamlessly with your repository, offering high-signal, codebase-aware insights without the noise often associated with other AI tools. Users can customize review standards by importing their own style guides, filtering out unwanted comments to maintain a focused review experience, and benefiting from codebase awareness that enhances comment quality. It also provides review insights with analytics on comment metrics, including issue categories, and offers suggested fixes that can be accepted with a single click.

Starting Price: $20 per month

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Korbit

Korbit is an AI-powered code review platform designed to enhance developer productivity by providing real-time, actionable feedback within pull requests. It integrates seamlessly with GitHub, GitLab, and Bitbucket, offering instant PR code reviews that identify issues and suggest fixes, akin to a human reviewer but faster. Korbit generates comprehensive PR descriptions, clarifying the context and purpose of changes, and writes summaries of its code reviews to help teams focus on critical issues. It offers a management dashboard that delivers insights into code quality, project status, and developer performance, aiding in effective team management. Korbit's adaptive reviews utilize deep project context, feedback, and custom settings to detect high-impact issues and provide explanations on how to resolve them. It also responds to questions and comments within the PR, offering replacement code to guide developers through any issues.

Starting Price: $9 per month

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Matter AI

Matter AI is an AI-powered code reviewer designed to streamline pull request workflows by generating detailed, context-aware summaries in seconds, eliminating the need for manual writing. It enhances code quality by identifying bugs, security risks, and performance issues before they reach production. By integrating with internal tools like Notion, JIRA, Confluence, and Linear, Matter AI provides reliable and trusted summaries and code analysis. Its AI explanations help reviewers understand complex code instantly, making approvals smoother and reducing review cycles. Matter AI operates with a strong emphasis on security, being SOC 2 Type II certified, and ensures data privacy by processing code in isolated environments without storing proprietary code. This tool is ideal for development teams aiming to accelerate their code review process while maintaining high standards of code quality and security.

Starting Price: $12 per month

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Entelligence

Entelligence AI is an AI-powered engineering intelligence platform designed to streamline development workflows, enhance collaboration, and boost productivity across the software development lifecycle. It automates code reviews and pull request (PR) analysis with intelligent agents, cutting review time, surfacing bugs early, and boosting engineering productivity. Entelligence's Deep Review feature detects complex issues across files with deep context analysis of the entire codebase, providing PR summaries, smart comments, and quick fixes. Entelligence AI also offers performance insights, tracking team performance, sprint progress, and code quality, monitoring output per engineer, review depth, and sprint assessments in real-time. Its self-updating documentation feature turns code into clear docs and refreshes them on every commit.

Starting Price: $29 per month

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Sourcery

Sourcery is an AI-powered automated code review and coding assistant designed to help developers and engineering teams improve code quality, catch bugs and security issues early, and maintain consistent standards across projects. It integrates directly into popular development workflows, including GitHub, GitLab, and IDEs like VS Code and JetBrains, providing instant, actionable feedback on pull requests and in-editor code changes rather than relying solely on traditional peer reviews. Sourcery analyzes diffs with a combination of large language model insights and static analysis to deliver clear summaries, line-by-line suggestions, high-level feedback, and visual diagrams that explain proposed changes, with the goal of offering review quality similar to what a colleague would provide. In the IDE, it functions as a real-time pair programmer that underlines potential improvements, enables one-click application of suggested fixes, and offers an AI chat.

Starting Price: $12 per month

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SonarQube Cloud

SonarSource

Maximize your throughput and only release clean code SonarQube Cloud (formerly SonarCloud) automatically analyzes branches and decorates pull requests. Catch tricky bugs to prevent undefined behavior from impacting end-users. Fix vulnerabilities that compromise your app, and learn AppSec along the way with Security Hotspots. With just a few clicks you're up and running right where your code lives. Immediate access to the latest features and enhancements. Project dashboards keep teams and stakeholders informed on code quality and releasability. Display project badges and show your communities you're all about awesome. Code Quality and Code Security is a concern for your entire stack, from front-end to back-end. That’s why we cover 24 languages including Python, Java, C++, and many others. Transparency makes sense and that's why the trend is growing. Come join the fun, it's entirely free for open-source projects!

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Rencore Code (SPCAF)

Rencore

Rencore Code (SPCAF) is the only solution on the market that analyzes and assures code quality for SharePoint, Microsoft 365 and Teams development by checking violations against over 1100 policies and checks regarding security, performance, best practices, maintainability, and supportability. Rencore Code (SPCAF) client both works as standalone desktop application or SaaS service. Dev teams run Rencore Code Server, allowing multiple developers to use it as a quality gate and seamlessly integrate it into any provisioning solution. Rencore Code (SPCAF) covers all developer and dev team needs from inventorizing code to troubleshooting and monitoring the performance of code. You can try Rencore Code (SPCAF) for free for 30 days. For more information, please visit our product page and follow Rencore on Twitter and LinkedIn.

Starting Price: $70 per user per month

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SonarQube for IDE

SonarSource

Easy to use, no configuration needed — just install from your favorite IDE marketplace and continue to code while SonarQube for IDE (formerly SonarLint) does its job. Your current linting tools may come with overhead – specialized tools for languages or longer setup and config time. With SonarQube for IDE, you can settle on a single solution to address your Code Quality and Code Security issues. We have you covered with hundreds of unique, language-specific rules to catch Bugs, Code Smells, and Security Vulnerabilities right in the IDE, as you code. From dangerous regex patterns to non-compliant coding standards, SonarQube for IDE is your true confidante in delivering error-free code. With an intelligent tool by your side, your mistakes are only visible to you so you can understand them, quickly remediate them, and learn along the way.

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CodeFactor

Get a glance at code quality for the whole project, recent commits, and the most problematic files. CodeFactor will track new and fixed issues for every commit and pull request. CodeFactor will try to show the most critical issues first based on issue code size, file change frequency, and file size so you can start fixing only what's important. Create and track issues or comments directly from code files or project issues pages. CodeFactor will update the status for GitHub or Bitbucket pull requests as well. CodeFactor allows you to toggle inspection for any repository branch on the fly. CodeFactor integrates with Slack to send code quality notifications for every commit in a branch or pull request. To install, go to the repository settings page. Straightforward pricing based on private repository number. Plain and simple with no hidden fees. Seamless integration into your workflow.

Starting Price: $19 per month

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Testwell CTC++

Testwell

Testwell CTC++ is a powerful instrumentation-based code coverage and dynamic analysis tool for C and C++ code. With certain add-on components CTC++ can be used also on C#, Java and Objective-C code. Further, again with certain add-on components, CTC++ can be used to analyse code basically at any embedded target machines, also in very small ones (limited memory, no operating system). CTC++ provides Line Coverage, Statement Coverage, Function Coverage, Decision Coverage, Multicondition Coverage, Modified Condition/Decision Coverage (MC/DC), Condition Coverage. As a dynamic analysis tool, CTC++ shows the execution counters (how many times executed) in the code, i.e. more than a plain executed/not executed information. You can also use CTC++ to measure function execution costs (normally time) and to enable function entry/exit tracing at test time. CTC++ is easy to use.

Starting Price: Free

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Best Free Code Quality Tools

Compare the Top Free Code Quality Tools as of January 2026

What are Free Code Quality Tools?

Aikido Security

Codespy

ThinkReview

Rollbar

Codecov

Stickler CI

Devel::Cover

Tarpaulin

coverage

Slather

NCover

JaCoCo

AppMap

PullRequest

GitChat

Early

Dependabot

Patched

PHPStan

Fynix

Diamond

Korbit

Matter AI

Entelligence

Sourcery

SonarQube Cloud

Rencore Code (SPCAF)

SonarQube for IDE

CodeFactor

Testwell CTC++

Best Free Code Quality Tools

Compare the Top Free Code Quality Tools as of January 2026

What are Free Code Quality Tools?

Aikido Security

Codespy

ThinkReview

Rollbar

Codecov

Stickler CI

Devel::Cover

Tarpaulin

coverage

Slather

NCover

JaCoCo

AppMap

PullRequest

GitChat

Early

Dependabot

Patched

PHPStan

Fynix

Diamond

Korbit

Matter AI

Entelligence

Sourcery

SonarQube Cloud

Rencore Code (SPCAF)

SonarQube for IDE

CodeFactor

Testwell CTC++

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