When would you choose Karate over Cucumber for API testing?

Karate advantages for API testing:

• No step definitions — DSL handles HTTP directly in the .feature file
• Built-in JSON Path / XML Path — no third-party assertion library needed
• Schema validation — out of the box, no JSON Schema library to wire up
• Mock server — Karate can simulate API responses without external tooling
• Parallel by default — runs scenarios in parallel with a single config flag

# Karate — everything in the feature file, no step defs needed
Scenario: Create an order and verify response
  Given url 'https://api.example.com'
  And   path '/orders'
  And   request { customerId: 1, amount: 99.99 }
  When  method POST
  Then  status 201
  And   match response.status == 'pending'
  And   match response.orderId == '#notnull'

Cucumber advantages:

• Scenarios read as business behaviour, understandable to stakeholders
• Tests span UI + API + DB in a single scenario
• Existing Java/JS ecosystem and libraries (RestAssured, Playwright, JDBC) are easily integrated
• DI, World, and step reuse patterns are mature

Decision heuristic:

• Pure API / contract / integration testing team → Karate
• Cross-layer behaviour tests with business stakeholder involvement → Cucumber
• Need to reuse existing Java test infrastructure → Cucumber
• New project, API-focused, wants minimum framework friction → Karate

They can coexist: Karate for API-layer tests, Cucumber for business behaviour E2E tests.