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testcritic

Qlty (formerly Code Climate Quality) vs Biome

Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.

Entry price

From $20 per contributor/month (Pro; Enterprise $30)

Free tier

Free and open source

Open source

What drives the bill

The metric that actually scales your invoice.

Priced per contributor. Free for K-12 and universities, 10% off for registered non-profits.

Free and open source. You pay in engineering time and CI minutes.

Free tier

Free plan with unlimited contributors, 1,000 analysis minutes and 100 AI autofixes a month.

Everything, self-hosted

Open source

MIT

Self-hostable

No-code authoring

Languages

RubyJavaScriptTypeScriptPythonPHPJavaGo
JavaScriptTypeScript

Platforms

WebAPI
WebAPI

Fits teams

StartupScale-up / mid-market
Solo / side projectStartupScale-up / mid-market

Adoption

Established

Qlty Software (spun out of Code Climate) · since 2011

Widely used

Biome / OSS community · since 2023

Strengths

  • Maintainability grading is easy to communicate to non-engineers.
  • Coverage and quality tracked together in one PR check.
  • Free for open source.
  • Dramatically faster than ESLint plus Prettier, which matters on pre-commit hooks.
  • One binary and one config replaces two toolchains.
  • Very good ESLint rule migration tooling.

Limitations

  • Letter grades oversimplify and can drive the wrong behaviour.
  • The Code Climate to Qlty transition means older documentation, URLs and integration guides still say Code Climate.
  • Velocity, the companion engineering-metrics product, was sunset — do not buy expecting it.
  • Rule coverage does not yet match ESLint's plugin ecosystem.
  • No support for framework-specific plugin ecosystems at ESLint's depth.
  • Young project, so expect churn.

Best for

Teams that want a simple maintainability signal in pull requests.

New JavaScript projects and teams frustrated by lint performance.

Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.