Compare 20 free code quality tools, free tiers, and developer deals. Verified pricing for What The Diff, Pullflow, codacy.com, Codeac.io, CodeFactor and more.

Free Code Quality Tools

20 verified free tiers and developer deals. Data verified through 2026-08-28.

What this name holds: Static analysis, review bots and coverage reporting that read the source without running the product.

3 other names here answer “how do I check the code and the browser”, and each holds a different list: Browser Automation (5), Testing (45), Web Scraping (23).

We track 20 code quality services with free tiers. What The Diff leads with a generous free tier. This category has been mostly stable — only 1 pricing change recorded across all vendors.

Vendor Tier Description Verified
What The Diff Free AI-powered code review assistant. The free plan has a limit of 25,000 monthly tokens (~10 PRs). 2026-07-31
Pullflow Free Superseded: As of 2026-08-28, pullflow.com reads: The Free plan is $0 forever for open source projects, startups, and small dev teams. It includes unlimited public repos, unlimited public users, and 5 private-repo users. We are not publishing our stored Pullflow terms beside it — our own pricing change record, discovered 2026-08-28, names them as the previous ones. Read what we recorded ↓ 2026-08-01
codacy.com Free 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 2026-08-13
Codeac.io Free 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) 2026-08-02
CodeFactor Free Automated Code Review for Git. The free version includes unlimited users, public repositories, and one private repo. 2026-08-05
coderabbit.ai Free AI-powered code review tool for GitHub/GitLab/Bitbucket. Free tier: basic PR summarization and reviews in IDE on unlimited public and private repositories, with a 14-day Pro trial included (no credit card). Paid Pro is $24/user/month billed annually and adds detailed reviews with 5 reviews/hour; Pro Plus adds 10 reviews/hour. Free-for-open-source may still apply but is no longer prominently featured on the pricing page. 2026-08-26
CodSpeed Free Automate performance tracking in your CI pipelines. Catch performance regressions before deployment, thanks to precise and consistent metrics. Free forever for Open Source projects. 2026-08-07
coveralls.io Free 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 2026-08-13
deepscan.io Free Advanced static analysis for automatically finding runtime errors in JavaScript code, free for Open Source 2026-08-02
DeepSource Free 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. 2026-08-04
DiffText Free Instantly find the differences between two blocks of code. Completely free to use. 2026-08-03
goreportcard.com Free Code Quality for Go projects, free for Open Source 2026-08-02
gtmetrix.com Free Website performance testing — Lighthouse-based reports with Core Web Vitals, waterfall charts, and optimization recommendations. Free account: testing from Seattle and London, dashboard with filters and tags, daily/weekly/monthly monitoring, e-mail alerts, and 1-month CrUX history. GTmetrix states no on-demand test or monitored-slot quantity for the free account; the cheapest paid plan (Lite, $5.99/mo) lists 50 monthly on-demand tests and 1 monitored slot. 2026-08-17
holistic.dev Free The #1 static code analyzer for Postgresql optimization. Performance, security, and architect database issues automatic detection service 2026-08-04
houndci.com Free Comments on GitHub commits about code quality, free for Open Source 2026-08-02
reviewable.io Free Code review for GitHub repositories, free for public or personal repos. 2026-08-04
scan.coverity.com Free Static code analysis for Java, C/C++, C# and JavaScript, free for Open Source 2026-08-28
scrutinizer-ci.com Free Continuous inspection platform, free for Open Source 2026-08-05
semanticdiff.com Free Programming language aware diff for GitHub pull requests and commits, free for public repositories 2026-08-06
tickgit.com Free Surfaces `TODO` comments (and other markers) to identify areas of code worth returning to for improvement. 2026-08-04

Frequently Asked Questions

What is the best free code quality service?
Based on our data, the most popular free code quality services include What The Diff, Pullflow, codacy.com, Codeac.io, CodeFactor. What The Diff offers a generous free tier on their Free plan. The best choice depends on your specific requirements.
How many free code quality tools are there?
We track 20 code quality services with free tiers on AgentDeals. These range from generous always-free tiers to limited trial periods. Each listing is verified with the actual pricing page.
How stable are code quality free tiers?
1 pricing change has been recorded across code quality vendors. Check our Stability Dashboard for per-vendor details.
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