Best Free Code Quality Tools

Code review for GitHub repositories, free for public or personal repos. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-22, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-22, found the same terms as an earlier read we had declined to record. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

The #1 static code analyzer for Postgresql optimization. Performance, security, and architect database issues automatic detection service. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-11, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-11, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Automated code reviews for PHP, Python, Ruby, Java, JavaScript, Scala, CSS, and CoffeeScript — free for open source. 4 users, 7 repos on free plan. Static analysis, security patterns, duplication detection, code complexity metrics. When we last read the page we cite for this offer, on 2026-11-01, we found the same terms as an earlier read we had declined to record, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-11-01, found the same terms as an earlier read we had declined to record. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Continuous inspection platform, free for Open Source. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-11, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-11, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Test coverage tracking — displays coverage reports with line-by-line detail, PR comments, and badge embeds. Free for open source repos with unlimited public repos. Supports 22+ languages. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-11, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-11, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Code Quality for Go projects, free for Open Source. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-11, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-11, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Programming language aware diff for GitHub pull requests and commits, free for public repositories. We could not read the page we cite for this offer when we last looked, on 2026-11-09, so we cannot confirm these terms today.

• −1 stale_verification We cannot confirm this offer: 8 consecutive re-check attempts have failed (most recently 2026-11-09 — page content too short (likely JS-rendered SPA); a rendering client read 449 characters), never confirmed since it was indexed. This is our inability to verify, not a change by the vendor. (a limit of ours, not a change by the vendor)

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. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-11, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-11, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Instantly find the differences between two blocks of code. Completely free to use. The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-22, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-22, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

Automated Code Review for Git. The free version includes unlimited users, public repositories, and one private repo. When we last read the page we cite for this offer, on 2026-11-03, we found a change we could not reconcile with the terms we publish, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-11-03, found the page different from the terms we hold. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)

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). The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-10-11, so we cannot confirm these terms today.

• −1 stale_verification Our last read of the vendor's pricing page, on 2026-10-11, could read no amount, tier or rate on the page. This is our confidence in the record, not a change by the vendor. (a limit of ours, not a change by the vendor)