Karate
BDD-style API testing with built-in mocks, performance testing, and UI automation. All in one lightweight framework.
Overview
Karate, created by Peter Thomas at Intuit in 2017, is an open-source API testing framework built on top of Cucumber-JVM. It uses a simple Gherkin-like syntax for API tests, making it accessible to non-programmers while still powerful enough for complex scenarios. Karate uniquely combines API testing, mocks, performance testing (via integration with Gatling), and even UI automation in a single framework.
Karate is particularly popular with teams that want BDD-style tests without the boilerplate of traditional Cucumber step definitions.
What it's used for
Karate excels when:
- BDD-style API testing: Readable tests that business stakeholders can review without Java knowledge.
- Mock services needed: Karate's built-in mock server can simulate dependencies with minimal configuration.
- Performance + functional combined: Reuse Karate tests as Gatling performance scenarios.
- Minimal setup required: Single JAR file, no complex dependencies or IDE configuration.
Pros & Cons
Pros
- Simple syntax — no Java coding required for most tests
- Built-in mock server for service virtualization
- Performance testing via Gatling integration
- UI automation support for end-to-end flows
- Single JAR deployment — minimal setup
Cons
- JVM-based — not suitable for non-Java teams
- Smaller community than Postman or REST Assured
- UI automation is basic compared to Playwright/Selenium
- Gatling integration requires Scala knowledge for advanced scenarios
- Debugging can be challenging for complex test flows
Platforms & Integrations
Karate runs on Windows, macOS, and Linux. It requires Java 8+ and Maven or Gradle. Tests are written in plain text files.
Pricing
| Tier | Cost | Includes |
|---|---|---|
| Open Source | Free | All features, mock server, Gatling integration, UI automation |
NZ Context
Karate has a growing following in NZ Java teams that want BDD-style API tests without Cucumber boilerplate. It is frequently mentioned in NZ testing meetups as a "hidden gem" for API automation. For teams already using Maven/Gradle, Karate adds almost zero setup overhead.
Alternatives
- Cucumber + REST Assured — More flexible but requires Java step definitions.
- Postman — GUI-first approach. Better for mixed teams and quick debugging.
- REST Assured — More powerful for pure Java teams that don't need BDD syntax.