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
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.
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