Testing
API Testing Tools, Plus E2E, Mobile & Load Testing
Choosing among API testing tools, E2E frameworks and load testers starts with choosing the layer you're testing. Each layer has a different best tool, and most teams need more than one.
- API testing. Run request collections with assertions from a CLI in CI: the Postman CLI or Newman for Postman,
bru runfor Bruno,hopp testfor Hoppscotch and Inso for Insomnia. Code-first teams can also call APIs directly from Playwright'srequestfixture. Compare the clients in Postman alternatives. - Browser E2E. Playwright (Apache-2.0) drives Chromium, Firefox and WebKit from JS/TS, Python, Java or .NET. Cypress (MIT) runs your tests inside the browser and has an interactive, time-travel debugger. Both can intercept and mock network requests (
page.route()andcy.intercept()), which often matters more than raw speed. - Mobile. Detox is a gray-box framework built for React Native, with tests written in JavaScript. Maestro describes flows in YAML for Android, iOS and web. Appium uses the W3C WebDriver protocol to automate native, hybrid and mobile-web apps from many languages.
- Load and performance. k6 (AGPL-3.0) is written in Go and scripted in JavaScript. Locust uses plain Python. Gatling supports Java, Kotlin, Scala and, more recently, JS/TS. Artillery uses YAML or Node scenarios and can drive Playwright for browser-level load.
Need to fake the backend instead? See the mocking section.
Every tool page lists licence, language and the date we last checked it. For a guided choice, try the tool picker.
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Top comparisons and guides
- Playwright vs Cypress (2026): architecture, network mocking, CI cost and a migration map
- How to mock APIs in Playwright:
page.route, HAR replay and MSW, tested on 1.64.1 - Keploy and a JS record/replay library: when to use which
- All comparisons
