Best Claude Code Plugins for Testing

Browser automation and end-to-end testing by Microsoft. Enables Claude to interact with web pages, take screenshots, fill forms, click elements, and perform automated browser testing workflows across Chromium, Firefox, and WebKit.

Chrome browser testing and performance analysis using Chrome DevTools Protocol (CDP). 27 professional-grade tools for web testing, performance measurement, accessibility validation, and browser automation.

Write new tests, run existing tests, analyze failures, and fix them while maintaining test integrity

Generate Storybook stories for components, manage visual regression tests, and browse existing stories from Claude Code

Preview and inspect web UIs that Claude builds — start, stop, click, fill forms, read console logs, capture screenshots, and monitor network requests, all inside Claude Code.

Automate API security directly in Claude Code with 42Crunch - automatically audit OpenAPI specs, detect vulnerabilities aligned with OWASP API Security risks (including BOLA/BFLA), and apply AI-powered fixes. Designed for AI-assisted development workflows, it provides continuous…

CodSpeed is the all-in-one performance testing toolkit. Dive into benchmarking results, flamegraphs, and performance comparisons — give Claude granular profiling context to pinpoint bottlenecks and autonomously iterate on performance via the CodSpeed MCP server.

Localhost web chat for testing the channel notification flow. No tokens, no access control, no third-party service.

A11y compliance testing with WCAG 2.1/2.2 validation, screen reader compatibility, and automated accessibility audits

Generate API contracts for consumer-driven contract testing

Fuzz testing for APIs with malformed inputs, edge cases, and security vulnerability detection

Create mock API servers from OpenAPI specs for testing

Automated API endpoint testing with request generation, validation, and comprehensive test coverage

Cross-browser testing with BrowserStack, Selenium Grid, and Playwright - test across Chrome, Firefox, Safari, Edge

Chaos testing for resilience with failure injection, latency simulation, and system resilience validation

API contract testing with Pact, OpenAPI validation, and consumer-driven contract verification

Generate realistic test data and database seed scripts for development and testing environments

Database testing utilities with test data setup, transaction rollback, and schema validation

Split datasets for training, validation, and testing

End-to-end test automation with Playwright, Cypress, and Selenium for browser-based testing

Run and manage integration test suites with environment setup, database seeding, and cleanup

Real mobile devices on demand via Kobiton's remote MCP — no emulators, no flaky CI. 12 tools across Devices, Sessions, and Apps surfaces, plus specialist agents for device picking, Appium capability reconciliation, and session triage.

Test load balancing strategies with traffic distribution validation and failover testing

Mobile app test automation with Appium, Detox, XCUITest - test iOS and Android apps

Mutation testing to validate test quality by introducing code changes and verifying tests catch them

Load testing and performance benchmarking with metrics analysis and bottleneck identification

Comprehensive codebase cleanup across 11 quality dimensions — dead code, duplication, weak types, circular deps, defensive cruft, legacy code, AI slop, type consolidation, security, performance, and async patterns. Confidence scoring and build verification gates.

Track and run regression tests to ensure new changes don't break existing functionality

Automated security vulnerability testing covering OWASP Top 10, SQL injection, XSS, CSRF, and authentication issues

Quick smoke test suites to verify critical functionality after deployments

Manage and update snapshot tests with intelligent diff analysis and selective updates

Analyze code coverage metrics, identify untested code, and generate comprehensive coverage reports

Generate realistic test data including users, products, orders, and custom schemas for comprehensive testing

Generate mocks, stubs, spies, and fakes for unit testing with Jest, Sinon, and test frameworks

Manage test environments with Docker Compose, Testcontainers, and environment isolation

Orchestrate complex test workflows with dependencies, parallel execution, and smart test selection

Generate comprehensive test reports with coverage, trends, and stakeholder-friendly formats

Automatically generate comprehensive unit tests from source code with multiple testing framework support

Visual diff testing with Percy, Chromatic, BackstopJS - catch unintended UI changes

Autonomous multi-agent development framework with spec-driven sprints. Write specs, run /sprint, and let coordinated agents (backend, frontend, QA, UI testing) handle implementation through self-iterating convergent loops.

Google Ventures Design Sprint methodology. Validate product ideas in 5 days with rapid prototyping, user testing, and structured decision-making.

Expert UX evaluator for CLIs and developer APIs, rates usability across 11 criteria with parallel evaluation agents

Production-grade Playwright testing toolkit. 9 skills, 3 agents, 55 templates, TestRail + BrowserStack MCP integrations. Generate tests, fix flaky failures, migrate from Cypress/Selenium.

Hypothesis testing, A/B experiment analysis, sample size calculation, and confidence intervals. 3 stdlib-only Python tools: Z-test/t-test/chi-square with effect sizes, sample size calculator with power tradeoffs, and Wilson score confidence intervals.

Manage prompts in production at scale: prompt versioning, A/B testing, prompt registries, regression prevention, and eval pipelines for production AI features. NOT for writing individual prompts, RAG design, or cost reduction (separate skills).

Product discovery skills for PMs: ideation, experiments, assumption testing, feature prioritization, and customer interview synthesis.

End-to-end feature orchestration with testing, security, performance, and deployment

Unit and integration test automation for Python and JavaScript with debugging support

Performance analysis, test coverage review, and AI-powered code quality assessment

API testing automation, request mocking, OpenAPI documentation generation, observability setup, and monitoring

Quantitative analysis, algorithmic trading strategies, financial modeling, portfolio risk management, and backtesting

WCAG accessibility auditing, compliance validation, UI testing for screen readers, keyboard navigation, and inclusive design

Production-grade Bash scripting with defensive programming, POSIX compliance, and comprehensive testing

Essential developer skills including Git workflows, SQL optimization, error handling, code review, E2E testing, authentication, debugging, and monorepo management

Multi-agent QA toolkit with 10 specialized agents covering the full QA lifecycle — orchestrator, environment-manager, functional-reviewer, test-scenario-designer, browser-validator, automation-writer, manual-validator, bug-reporter, release-analyzer, and smart-test-selector. Sta…

Python development suite: testing, performance optimization, async patterns, and packaging guidance

Verifies API contracts between services using consumer-driven contracts, schema validation, and tools like Pact. Use when testing microservices communication, preventing breaking changes, or validating OpenAPI specifications.

HTTP API testing for TypeScript (Supertest) and Python (httpx, pytest). Test REST APIs, GraphQL, request/response validation, authentication, and error handling.

Comprehensive Cloudflare Workers platform guide covering runtime APIs, testing (Vitest), CI/CD, observability, framework integration, performance, security, and migration. Use for Workers development, deployment, debugging, or optimization.

7-phase frontend design review with accessibility (WCAG 2.1 AA), responsive testing, visual polish. Use for PR reviews, UI audits, or encountering contrast issues, broken layouts, accessibility violations, inconsistent spacing, missing focus states.

Generate Jest unit tests for JavaScript/TypeScript with mocking, coverage. Use for JS/TS modules, React components, test generation, or encountering missing coverage, improper mocking, test structure errors.

Mobile app testing with unit tests, UI automation, performance testing. Use for test infrastructure, E2E tests, testing standards, or encountering test framework setup, device farms, flaky tests, platform-specific test errors.

Validate test effectiveness with mutation testing using Stryker (TypeScript/JavaScript) and mutmut (Python). Find weak tests that pass despite code mutations. Use to improve test quality.

Pinia v3 Vue state management with defineStore, getters, actions. Use for Vue 3 stores, Nuxt SSR, Vuex migration, or encountering store composition, hydration, testing errors.

Deploy production recommendation systems with feature stores, caching, A/B testing. Use for personalization APIs, low latency serving, or encountering cache invalidation, experiment tracking, quality monitoring issues.

Creates detailed technical specifications for software projects covering requirements, architecture, APIs, and testing strategies. Use when planning features, documenting system design, or creating architecture decision records.

Detect test smells, overmocking, flaky tests, and coverage issues. Analyze test effectiveness, maintainability, and reliability. Use when reviewing tests or improving test quality.

Modern TypeScript/JavaScript testing with Vitest. Fast unit and integration tests, native ESM support, Vite-powered HMR, and comprehensive mocking. Use for testing TS/JS projects.

End-to-end testing with real dependencies - no mocks allowed; scenarios with real data are the only source of truth