How do you test RESTful APIs for errors?

1 Validate the request

The first step in testing RESTful APIs for errors is to validate the request that you send to the API endpoint. You need to check if the request method, headers, parameters, and body are correct and comply with the API specifications. You can use tools like Postman, Insomnia, or Curl to create and send requests to the API and inspect the results. You can also use unit testing frameworks like Mocha, Jest, or Pytest to write automated tests for the request validation.

2 Check the status code

The next step in testing RESTful APIs for errors is to check the status code that the API returns in the response. The status code indicates the outcome of the request, whether it was successful, failed, or redirected. You should verify that the status code matches the expected value for each scenario, and that it follows the HTTP standards. For example, a 200 status code means OK, a 400 status code means Bad Request, and a 500 status code means Internal Server Error. You can use the same tools and frameworks as in the previous step to check the status code.

3 Analyze the response body

The third step in testing RESTful APIs for errors is to analyze the response body that the API returns in the response. The response body contains the data or message that the API provides to the client. You should verify that the response body is in the expected format, such as JSON, XML, or plain text, and that it contains the correct data or message for each scenario. You should also check for any errors or warnings that the API might return in the response body, and how they affect the client. You can use tools like JSONLint, XML Validator, or Regex Tester to validate and parse the response body.

5 Test the business logic

The fifth step in testing RESTful APIs for errors is to test the business logic that the API implements in the backend. The business logic refers to the rules, calculations, and validations that the API applies to the data and the requests. You should verify that the business logic is correct and consistent for each scenario, and that it handles any exceptions or edge cases gracefully. You should also check for any logical errors, such as incorrect assumptions, faulty algorithms, or inconsistent outcomes. You can use tools like debugger, logger, or tracer to inspect and trace the business logic.

6 Test the security

The sixth and final step in testing RESTful APIs for errors is to test the security that the API provides to the clients and the data. The security refers to the measures that the API takes to prevent unauthorized access, modification, or disclosure of the data and the requests. You should verify that the API uses proper authentication, authorization, encryption, and validation mechanisms to protect the data and the requests. You should also check for any security vulnerabilities, such as injection attacks, cross-site scripting, or broken access control. You can use tools like OWASP ZAP, Nmap, or Burp Suite to scan and exploit the security flaws.

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?