How to: Code Quality
* [beanstalkapp.com](https://beanstalkapp.com/) — A complete workflow to write, review, and deploy code), a free account for one user, and one repository with 100 MB of storage
  * [codacy.com](https://www.codacy.com/) — Automated code reviews for PHP, Python, Ruby, Java, JavaScript, Scala, CSS, and CoffeeScript, free for unlimited public and private repositories
  * [Codeac.io](https://www.codeac.io/infrastructure-as-code.html?ref=free-for-dev) - 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)
  * [codecov.io](https://codecov.io/) — Code coverage tool (SaaS), free for Open Source and one free private repo
  * [CodeFactor](https://www.codefactor.io) — Automated Code Review for Git. The free version includes unlimited users, public repositories, and one private repo.
  * [coderabbit.ai](https://coderabbit.ai) — 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.
  * [CodSpeed](https://codspeed.io) - Automate performance tracking in your CI pipelines. Catch performance regressions before deployment, thanks to precise and consistent metrics. Free forever for Open Source projects.
  * [coveralls.io](https://coveralls.io/) — Display test coverage reports, free for Open Source
  * [deepscan.io](https://deepscan.io) — Advanced static analysis for automatically finding runtime errors in JavaScript code, free for Open Source
  * [DeepSource](https://deepsource.io/) - 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.
  * [DiffText](https://difftext.com) - Instantly find the differences between two blocks of code. Completely free to use.
  * [eversql.com](https://www.eversql.com/) — EverSQL - The #1 platform for database optimization. Gain critical insights into your database and SQL queries automatically.
  * [gerrithub.io](https://review.gerrithub.io/) — Gerrit code review for GitHub repositories for free
  * [goreportcard.com](https://goreportcard.com/) — Code Quality for Go projects, free for Open Source
  * [gtmetrix.com](https://gtmetrix.com/) — Reports and thorough recommendations to optimize websites
  * [holistic.dev](https://holistic.dev/) - The #1 static code analyzer for Postgresql optimization. Performance, security, and architect database issues automatic detection service
  * [houndci.com](https://houndci.com/) — Comments on GitHub commits about code quality, free for Open Source
  * [reviewable.io](https://reviewable.io/) — Code review for GitHub repositories, free for public or personal repos.
  * [scan.coverity.com](https://scan.coverity.com/) — Static code analysis for Java, C/C++, C# and JavaScript, free for Open Source
  * [scrutinizer-ci.com](https://scrutinizer-ci.com/) — Continuous inspection platform, free for Open Source
  * [semanticdiff.com](https://app.semanticdiff.com/) — Programming language aware diff for GitHub pull requests and commits, free for public repositories
  * [shields.io](https://shields.io) — Quality metadata badges for open source projects
  * [sonarcloud.io](https://sonarcloud.io) — 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

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