What external tools or services do you use for API interface testing and verification?

The following tools and services are often used for testing and verifying APIs:

• Postman — a popular GUI tool for manual testing of REST APIs, allows creating requests, saving collections, and automating tests.

• Swagger / OpenAPI — tools for documenting APIs and generating tests based on specifications.

• SoapUI — a tool for testing SOAP and REST services with support for complex scenarios.

• Insomnia — a convenient client for testing HTTP requests with support for GraphQL.

• JMeter — for load testing APIs.

• curl — a command-line tool for sending HTTP requests, useful for quick checks.

• Automation using frameworks: for example, in Python — requests + pytest, in JavaScript — jest + supertest.

The choice of tool depends on the task: for manual testing and debugging — Postman or Insomnia, for automation — appropriate libraries and frameworks.