Stryker Mutator

Self-hosted · API

Freedom report

Two barsScore 6.3

Free tierA free tier is on its own pricing page
Open codeNo open-source code on record
Runs widely0 of 6 device platforms
DocumentedPlans, terms and facts published

Stryker Mutator is ranked #4 of 25 in mutation testing tools on Freedom251. It runs on API, Self-hosted. There is a free plan.

Stryker Mutator plans and pricing

All plans

Stryker Mutator Free Open source mutation testing for JavaScript/TypeScript, C# and Scala · Apache 2.0 license stryker-mutator.io · 30 Sept 2026

Compared on mutation testing tools

Free plan: Yes
Supported languages: JavaScript, TypeScript, C#, Scala
Test frameworks: Cucumber, Jasmine, Jest, Karma, Mocha, Tap, Vitest, command runner
Incremental analysis: Yes
Parallel execution: Yes
Surviving mutant reports: Yes
Mutation quality gate: Yes
Mutation operators: Arithmetic Operator, Array Declaration, Block Statement, Boolean Literal, Conditional Expression, Equality Operator, Logical Operator, Method Expression, Object Literal, Optional Chaining, Regex, String Literal, Unary Operator, Update Operator

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The record

Purpose: Stryker performs mutation testing by inserting changes into code and running unit tests against the changed code to assess test effectiveness.
Mutations: The product site says Stryker supports more than 30 mutations.
Performance: Stryker uses code analysis and parallel test runner processes to speed up mutation testing.
Test runners: Stryker is described as test runner agnostic, and StrykerJS documentation lists plugins for test runners including Cucumber, Jasmine, Jest, and Karma.
Dashboard: The open source dashboard hosts mutation testing reports in the cloud and provides mutation score badges; it is free to use for open source.
Dashboard integration: The dashboard setup uses a GitHub account and enables reporting for a repository.
Report API: Reports can be sent directly from Stryker or by HTTP PUT with an API key, and reports can contain a full report or mutation score only.
Security: Stryker says it mutates only source code to avoid false positives.
License: Stryker is released under the Apache 2.0 license.
Setup: Stryker.NET is installed using NuGet, while the Stryker4s guide provides sbt, Mill, and Maven plugin setup paths.
Support: The documentation directs users to Slack for help and bug discussions, with bug reporting guidance also available.
Runtime consideration: Stryker’s FAQ notes that mutation runs can be slow and recommends improving unit test performance and restricting mutations to needed files.
Dashboard provider limit: The dashboard documentation says its backend currently supports github.com as a Git provider.
Price from: Free

Where it ranks on Freedom251

Best Mutation Testing Tools in 2026#4 of 25

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Sources

stryker-mutator.io/docs/· checked 30 Sept 2026
stryker-mutator.io· checked 30 Sept 2026
stryker-mutator.io/docs/stryker-js/plugins/· checked 30 Sept 2026
stryker-mutator.io/docs/General/dashboard/· checked 30 Sept 2026
stryker-mutator.io/docs/stryker-net/introduction/· checked 30 Sept 2026
stryker-mutator.io/docs/General/faq/· checked 30 Sept 2026