Karate vs. Rest-assured Karate vs. Postman Karate vs. Playwright Karate vs. Katalon Karate vs. Cypress

Karate vs. Postman

Postman is widely used as a tool for exploring APIs and for saving API request details as “collections”. Collections are convenient for sharing with team members.

The UI driven approach of Postman has made it popular especially with non-programmers. However, UI driven approaches have a trade-off where it is harder to script complex tests or re-use code.

Postman’s sweet spot is in making API requests and saving them. But testing (assertions) and chaining of API responses (end-user flows) is not straight-forward and requires the use of JavaScript.

Karate has had a very different focus from day one. Karate :

  • Is code-based with emphasis on testing API responses for accuracy via built-in assertions
  • Encourages test-flows that call multiple APIs in sequence, hence simulating real-life end-user behaviour
  • Gives more power to developers as it is natively scriptable, and allows for data-driven testing, looping and re-use.
  • Being code-driven, teams can collaborate naturally via Git without needing to leave the IDE.

Please refer table below for detailed comparison.

Postman Karate

Scripting

UI-driven / No-Code, but Testing (assertions) requires javaScript Code.

Low-Code.

Assertions

Very basic, requires JS skills and additional Libraries for more.

Built-in, comprehensive yet readable.

Chaining
  • Not Intuitive. Cannot be read on one page.
  • Simulating an end-user flow is possible, but passing data requires extra JS.

Designed to support multiple API calls within a single test flow.

Tests are reports are readable by business/users.

Power and Re-Use
  • Data-driven testing/looping is hard and requires extra JS
  • Code re-use is clunky and limited to JS embedded within a collection.

Built-in support for data-driven testing and loops. First-class support for common functions, header/auth manipulation and environment switching.

Extending via Code

Not Supported.

For advanced use-cases, Karate can call Java code. This allows for testing databases. async systems (e.g. Kafka and Queues) and CL processes.

Parallel Execution

Not Supported. Even if you manually split test suites and run them in parallel, you cannot get an aggregated report.

Tests are executed on multiple threads. Typical time savings are 10x or more. A single aggregated report is generated.

Tags
  • The ability to tag a Postman collection for searching was added only in 2023.
  • Users cannot use tags to filter test execution

Built-in. Can be used for execution flexibility, dry-run reports, test coverage and linking to test-management and reporting tools.

Reports

Requires additional plugins or Saa/Postman enterprise.

Built-in, rendered locally, can be shared as HTML.

Version Control

Postman collections are opaque blobs of JSON and not Git-friendly. Test authoring requires a separate workflow. Developers and tasters tend to work in silos. Tests are stored in the Postman cloud. You depend on Postman to track change history.

Karate is local-first and code-driven. Tests are plain-text and version-controlled or change-tracked just like normal code. You see the history of your implementation code and tests together. Team collaboration happens naturally via Git.

IDE Support and Debug

Auto-complete/intelli-sense is limited and only for the JS that Postman supports. You cannot use an ID debugger or step-back within a bug session VS Code support was announced in 2023 but appears to be no different.

First-class IDE support in both VS Code and IntelliJ. You can debug a Karate test and even step-back and hot-reload code within a debug session.

CI Integration

Test-execution in CI pipelines requires a separate executable (Newman or the new Postman CLI), Teams need to export a collection or sign into Postman enterprise Support for industry standard formats (eg. JUnit XVL) is non-existent or via community plugins only for Newman. There are limits to free tier CLI test execution.

The same binary is the test-execution engine. Karate can also be consumed via Maven, Gradle, or Docker. No data leaves the firewall. No limit on number of tests or downloads. Plugs into any Cl engine because the industry standard JUnit XML and Cucumber JSON formats are output.

Mocks

Postman supports API mocks but requires you to use their public servers. Complex mocks are hard to implement.

Karate API mocks can be deployed locally or anywhere within your network. Mocks can be highly dynamic with litle effort.

UI Testing

Not Supported.

Karate supports even hybrid-tests where you can mix API and UI tests in the same script.

Performance Testing

Postman support for this is very new and only local-execution is supported (no cloud). Only a single collection is supported.

You can model complex load-models and combine mutiple Karate script and user- flows. You can choose to run your tests in the cloud or as part of your CI/CD.