Compare 20 free code quality tools, free tiers, and developer deals. We could not confirm today's terms for 18 of them: on 13 the page we cite did not answer, and on 5 our own read did not confirm them. Each row says why. Nothing on record contradicts our terms for What The Diff, scan.coverity.com.

Free Code Quality Tools

20 free tiers and developer deals. Catalogue dates here run to 2026-09-26.

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 (10), Testing (45), Web Scraping (23).

We track 20 code quality services with a free tier we hold as current. This category has been stable — no pricing changes recorded across any vendor.

Vendor Tier Description Read / catalogue date
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 Pullflow offers an AI-enhanced platform for code review collaboration across GitHub, Slack, and VS Code. — 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.Our read on 2026-09-10 found the page different from the terms we hold, and we hold no confirmation of the terms we publish. 2026-09-10 / 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 metricsWhen we last read the page we cite for this offer, on 2026-09-19, we could read no amount, tier or rate on the page, so we cannot confirm these terms today. 2026-09-19 / 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)The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 2026-08-02
CodeFactor Free Automated Code Review for Git. The free version includes unlimited users, public repositories, and one private repo.The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 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.Our read on 2026-09-26 found the page different from the terms we hold, and we hold no confirmation of the terms we publish. 2026-09-26 / 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.The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 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+ languagesThe page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 2026-08-13
deepscan.io Free Advanced static analysis for automatically finding runtime errors in JavaScript code, free for Open SourceThe page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 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.The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 2026-08-04
DiffText Free 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 2026-09-10, so we cannot confirm these terms today. 2026-09-10 / 2026-08-03
goreportcard.com Free Code Quality for Go projects, free for Open SourceThe page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 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.The page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-14, so we cannot confirm these terms today. 2026-09-14 / 2026-08-17
holistic.dev Free The #1 static code analyzer for Postgresql optimization. Performance, security, and architect database issues automatic detection serviceThe page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 2026-08-04
houndci.com Free Comments on GitHub commits about code quality, free for Open SourceOur read on 2026-09-28 found the page different from the terms we hold, and we hold no confirmation of the terms we publish. 2026-09-28 / 2026-08-02
reviewable.io Free 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 2026-09-10, so we cannot confirm these terms today. 2026-09-10 / 2026-08-04
scan.coverity.com Free Static code analysis for Java, C/C++, C# and JavaScript, free for Open Source 2026-09-26
scrutinizer-ci.com Free Continuous inspection platform, free for Open SourceThe page we cite for this offer states no amount, tier or rate we can read when we last looked, on 2026-09-02, so we cannot confirm these terms today. 2026-09-02 / 2026-08-05
semanticdiff.com Free Programming language aware diff for GitHub pull requests and commits, free for public repositoriesWe could not read the page we cite for this offer when we last looked, on 2026-09-14, so we cannot confirm these terms today. 2026-08-06 · tried 2026-09-14, no read
tickgit.com Free Surfaces `TODO` comments (and other markers) to identify areas of code worth returning to for improvement.When we last read the page we cite for this offer, on 2026-09-26, we found no earlier figure of ours for the page to have narrowed, so we cannot confirm these terms today. 2026-09-26 / 2026-08-04

Frequently Asked Questions

What is the best free code quality service?
We publish no ranking of these. Nothing we record measures popularity or generosity, so naming a best or a top few would be our preference rather than our data. We hold 20 Code Quality services in our catalogue, listed in the table above with each one's tier, published terms and the read and catalogue dates we hold. Our ranking rule is published at /criteria.
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. Of the 20 Code Quality entries we hold, 1 carries terms a read confirmed in the last 90 days.
How stable are code quality free tiers?
No pricing changes have been recorded for any code quality vendor we track.
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