What are the best API debugging techniques?

1 Use API testing tools

One of the first steps to debug an API is to use a tool that can send and receive requests and responses. There are many tools available, such as Postman, Insomnia, or curl, that can help you test different endpoints, parameters, headers, and body formats. You can also use these tools to automate your tests, check for errors, and validate your responses against a schema or specification.

2 Inspect network traffic

Sometimes, the problem is not in the API itself, but in the network layer that connects it to other applications. To debug network issues, you need to inspect the traffic that flows between your client and your server. You can use tools like Wireshark, Fiddler, or Charles Proxy to capture and analyze packets, headers, cookies, and encryption. You can also use these tools to simulate different network conditions, such as latency, bandwidth, or errors.

4 Use breakpoints and debuggers

Sometimes, you need to go deeper into the code to debug an API. Breakpoints and debuggers can help you pause the execution of your code and inspect the values of variables, expressions, and objects. You can also use breakpoints and debuggers to step through your code, line by line, and watch how it changes the state of your program. You can use tools like Visual Studio Code, PyCharm, or Chrome DevTools to set breakpoints and debug your code.

5 Use mock and stub services

Sometimes, you need to debug an API that depends on other services that are not available or reliable. Mock and stub services can help you simulate the behavior and responses of those services, without actually calling them. You can use mock and stub services to isolate your API from external dependencies, test different scenarios, and reduce costs and risks. You can use tools like MockServer, WireMock, or Nock to create mock and stub services.

6 Review documentation and contracts

Finally, one of the best API debugging techniques is to review the documentation and contracts that define how your API should work and interact with other services. Documentation and contracts can help you understand the requirements, expectations, and specifications of your API. They can also help you avoid misunderstandings, inconsistencies, and conflicts with other developers and users. You can use tools like Swagger, OpenAPI, or Postman to create and manage your documentation and contracts.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?