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testcritic

Qlty (formerly Code Climate Quality) vs ESLint

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-marketEnterprise

Adoption

Established

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

Category standard

OpenJS Foundation · since 2013

Strengths

  • Maintainability grading is easy to communicate to non-engineers.
  • Coverage and quality tracked together in one PR check.
  • Free for open source.
  • The plugin ecosystem lets you enforce almost any convention as a rule.
  • Autofix handles a large share of findings without human effort.
  • Universal — every JavaScript tool integrates with it.

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.
  • Configuration is a real project of its own, and the flat-config migration caused significant churn.
  • Slow on large codebases without caching.
  • Rule sprawl produces bikeshedding unless someone owns the config.

Best for

Teams that want a simple maintainability signal in pull requests.

Every JavaScript and TypeScript project.

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