Mutineer
Mutineer: A focused open-source mutation testing CLI for Jest and Vitest teams. Ranked #13 of 25 in Mutation Testing Tools by our editors (6.0/10); pricing: Open source; best for typeScript teams using Jest or Vitest.
At a glance
- Editor score6.0 / 10
- PricingOpen source
- Best forTypeScript teams using Jest or Vitest
- Paid fromNone
- Mutation quality gateYes
- Facts checked20 Sep 2026
Where it wins
- AST-safe mutations with changed-file and changed-import scoping
- Parallel workers and coverage-based test selection
- Kill-rate thresholds, JSON output, and per-file reports
Where it doesn't
- Focused on JavaScript, TypeScript, and Vue component projects
- Runner support centers on Vitest and Jest
- Mutation operators follow a defined set of code changes
Our verdict on Mutineer
Mutineer is an open-source command-line mutation testing framework for JavaScript and TypeScript projects. It is aimed at teams using Vitest or Jest, with support for Vue single-file components as part of its mutation scope. The tool modifies source code with AST-safe mutations, runs relevant tests, detects escaped mutants, and reports kill rates and per-file results. It is distributed as an npm package under the MIT license.
Its strongest practical advantage is targeted analysis. Mutineer can focus runs on changed files and changed imports, while per-test coverage-based selection helps connect mutations with relevant tests. Parallel worker execution is available for mutation runs, and TypeScript type-check pre-filtering can remove unsuitable candidates before test execution. The published feature set also includes mutation operators for equality, boundaries, logical operators, arithmetic, return values, and Vue composition and template directives.
For CI quality gates, Mutineer provides configurable minimum kill-rate thresholds, escaped-mutant reporting, per-file results, and JSON report output. That gives teams several ways to expose mutation quality in automated workflows without moving to a vendor-hosted service. Its scope is deliberately focused: teams working primarily with JavaScript or TypeScript and Vitest or Jest should find the feature set aligned with their stack, while projects built around other languages or test frameworks should choose a tool with broader ecosystem coverage. Mutineer is a strong fit when incremental analysis and test-selection controls matter more than a wide runner matrix.
Mutineer pricing
Mutineer fact sheet
| Free plan | Not verified |
|---|---|
| Paid from | None |
| Supported languages | JavaScript, TypeScript |
| Test frameworks | Vitest, Jest |
| Incremental analysis | Yes |
| Parallel execution | Yes |
| Surviving mutant reports | Yes |
| Mutation quality gate | Yes |
| Mutation operators | Equality flips, boundary changes, logical operator changes, arithmetic operator changes, return-value changes, Vue composition and template-directive mutations |
| Deployment | Self-hosted |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Open source |
| Website | github.com |
| Facts checked | 20 Sep 2026 |
Alternatives to Mutineer
- ArcMutateA broad JVM mutation testing suite with CI workflows, quality gates and a free plan.9.8
- PITA mature open-source choice for Java teams that need configurable mutation analysis.8.2
- Stryker MutatorA broad, open-source mutation testing toolkit with strong CI and reporting support.7.7
See all Mutineer alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026
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