DevTiers

A complete workflow to write, review, and deploy code), a free account for one user, and one repository with 100 MB of storage

Automated code reviews for PHP, Python, Ruby, Java, JavaScript, Scala, CSS, and CoffeeScript, free for unlimited public and private repositories

Automated Infrastructure as Code review tool for DevOps integrates with GitHub, Bitbucket, and GitLab (even self-hosted). In addition to standard languages, it also analyzes Ansible, Terraform, CloudFormation, Kubernetes, and more. (open-source free)

Code coverage tool (SaaS), free for Open Source and one free private repo

Automated Code Review for Git. The free version includes unlimited users, public repositories, and one private repo.

AI-powered code review tool that integrates with GitHub/GitLab. Free tier includes 200 files/hour, 3 reviews per hour, and 50 conversations/hour. Free forever for open source projects.

Automate performance tracking in your CI pipelines. Catch performance regressions before deployment, thanks to precise and consistent metrics. Free forever for Open Source projects.

Display test coverage reports, free for Open Source

Advanced static analysis for automatically finding runtime errors in JavaScript code, free for Open Source

DeepSource continuously analyzes source code changes, finding and fixing issues categorized under security, performance, anti-patterns, bug-risks, documentation, and style. Native integration with GitHub, GitLab, and Bitbucket.

Instantly find the differences between two blocks of code. Completely free to use.

EverSQL - The #1 platform for database optimization. Gain critical insights into your database and SQL queries automatically.

Gerrit code review for GitHub repositories for free

Code Quality for Go projects, free for Open Source

Reports and thorough recommendations to optimize websites

The #1 static code analyzer for Postgresql optimization. Performance, security, and architect database issues automatic detection service

Comments on GitHub commits about code quality, free for Open Source

Code review for GitHub repositories, free for public or personal repos.

Static code analysis for Java, C/C++, C# and JavaScript, free for Open Source

Continuous inspection platform, free for Open Source

Programming language aware diff for GitHub pull requests and commits, free for public repositories

Quality metadata badges for open source projects

Automated source code analysis for Java, JavaScript, C/C++, C#, VB.NET, PHP, Objective-C, Swift, Python, Groovy and even more languages, free for Open Source