Error Handling and Debugging Tips for Complex API Calls

[kevincalori]

Hello everyone,

I need some advice on handling complex API calls and error management in Postman. I am currently working on a project that involves interacting with a highly intricate API; and I’ve run into a few challenges that I hope this community can help with.

I have noticed that the API returns errors in a variety of formats; which can be inconsistent and sometimes confusing. This inconsistency makes it difficult to create robust tests or extract useful information for debugging. For instance; the error responses might vary in structure and field names depending on the endpoint / the type of error encountered.

Some of the API requests require dynamic parameters that are based on previous responses or user inputs. Managing these dynamic parameters and ensuring that the API responses remain consistent has been a challenge. The format of the responses can change based on these parameters; complicating the validation process.

When it comes to debugging; I often need to deal with complex nested JSON structures in the API responses. Extracting specific pieces of information and validating them effectively has proven to be quite cumbersome. I am looking for efficient ways to handle and validate these complex responses.

What are the best practices for handling and validating error responses in Postman; especially when dealing with inconsistent formats?

How do you approach testing requests with dynamic parameters in Postman? Are there any specific features / techniques that can help manage and validate these parameters?

What tips do you have for debugging complex API responses in Postman? How do you efficiently handle and validate nested JSON structures?

Do you have any general advice for working with complex APIs in Postman? How can I ensure that my testing and debugging processes are both robust and reliable? I have referred https://blog.postman.com/best-practices-for-api-error-handling-aws developer associate documentation guide but still need advice.

I would greatly appreciate any experiences you can share. Thank you in advance for your help!

Best regards

[michaelderekjones (Mike Jones)]

Best practice is subjective, so I’m not going to say that anything below is best practice, but this is my advice as a starter for 10.

You need to think of API testing as the same as you would for any other type of testing.

First thing is to forget the tooling for a moment, take a step back and work out the coverage of your testing.

Whether its UI testing, performance, security or API testing. If you don’t get the coverage right, the tool used to run those tests will be irrelevant.

This will include happy path successful requests, but to test an API correctly you will need a lot of negative tests. Failed authentication, incorrect body sent, etc. If there are 5 mandatory fields for the body, then that is at least 5 negative tests before you even start.

You need to be in control of your test data, so you need a clearly defined strategy for test data including the data needed for those negative tests.

You should never have inconsistent responses if you take control of your test data. The test should run exactly the same, each and every time it runs. It should always return the same response (and you want it to fail and alert you when it doesn’t).

You’ll have to explain what you mean by dynamic parameters. You shouldn’t need any dynamic parameters if you are in control of your test data and the system is in the correct known state.

Leverage the pre-request scripts to ensure that the system under test is in the correct conditions for the test. That it is in the correct known state. I prefer this method over relying on a tear down script that might not have completed. Check the condition of the system before the request\test if possible.

You shouldn’t really have unknown inconsistencies if you have tested the API in depth. Unknown inconsistences\errors should be investigated and fixed which may involve adding more requests and tests to your coverage.

You don’t say if this API is developed in-house or if you are consuming third party API’s that you have little control over.

You can validate the expected structure of responses using the following methods.

Postman test script examples | Validate response structure

Last bit of advice is to test each API call separately and as part of expected work flows. It helps if\when you need to troubleshoot an issue.