ESLint vs Qlty (formerly Code Climate Quality)
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
Free and open source
Open sourceFrom $20 per contributor/month (Pro; Enterprise $30)
Free tierWhat drives the bill
The metric that actually scales your invoice.
Free and open source. You pay in engineering time and CI minutes.
Priced per contributor. Free for K-12 and universities, 10% off for registered non-profits.
Free tier
Everything, self-hosted
Free plan with unlimited contributors, 1,000 analysis minutes and 100 AI autofixes a month.
Open source
MIT
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Category standard
OpenJS Foundation · since 2013
Established
Qlty Software (spun out of Code Climate) · since 2011
Strengths
- 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.
- Maintainability grading is easy to communicate to non-engineers.
- Coverage and quality tracked together in one PR check.
- Free for open source.
Limitations
- 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.
- 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.
Best for
Every JavaScript and TypeScript project.
Teams that want a simple maintainability signal in pull requests.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.