Karate vs. Playwright

Karate has the following advantages over Playwright:

  • Better and more comprehensive API testing support.
  • Easier and more powerful API assertions support.
  • Simpler syntax – which non-programmers can pick up easily
    • The issues with JavaScript for test-automation (especially “async”, “await” and “promises” are explained in detail below.
  • Support for API mocks (which can be included in UI automation)
    • Since Karate includes API mocking capabilities, you can set up UI tests that use fake API responses served by Karate.
  • Unified API and UI test automation – enabling hybrid tests.
  • Re-use API tests as performance tests.

Here are some evaluation criteria for choosing between Playwright and Karate for UI test-automation:

  • Karate uses real-browsers
    • Playwright uses a “patched” browser, which requires these browsers to be installed locally, which adds to the setup and installation complexity. There will be a need to make sure the Playwright versions are synced to what is required. There is also a small risk that results using the Playwright browser may not reflect real browser behaviour.
  • Running tests in parallel
    • While it is possible in Playwright, it requires using NodeJS for running tests in parallel, which is more complicated and less reliable.
    • Karate supports parallelization using the JVM and also on Docker or distributed nodes.
  • When using JavaScript / NodeJS – tests are Asynchronous By Default:
    • For any developer who has experience with OOP and programs that manage state-promises, async and await are quite advanced programming concepts, and expecting developers to master these for the sake of test-automation is a stretch. Even experienced developers make mistakes in these areas. And if you cannot debug your tests, that is a very severe limitation.
    • Karate has no such limitations
      • You can use variables
      • Steps run in the exact order you write them, just as you expect in a normal programming language
      • You can actually use an IDE to step-through and debug your tests
      • The debugger can actually step-back and hot-reload changes, refer this video: (timestamp 1:30)
  • Debugging
    • Already covered in the previous point, you can step-back and use a debugger more effectively in Karate

Note: Karate has experimental support for using Playwright as a browser-driver or test-runner. This means you can:

  • Write tests using Karate, get the benefits of hybrid and API tests.
  • Use the advanced debugging features and parallel execution.
  • Be “future proof” – which means if you want to switch to Playwright or a provider like SauceLabs or BrowserStack that supports Playwright, it will be easy to switch.