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Common Challenges in API Testing and How to Handle Them

Author: Pricilla Bilavendran

Last updated: May 29, 2024

challenges in api testing
Table of Contents

Welcome back to another interesting blog about API testing. You might need to start testing your APIs at some point, and there are some considerations before getting started. 


challenges in api testing


So, the time spent on the initial analysis and planning is worth it for every tester to have a smooth ride during your API Testing process. Here are a few questions to ask in your analysis to improve your testers’ experience:

  1. What is this API for?
  2. Is this going to be internal?
  3. Who should be ideally using this API?
  4. How are we going to test this API?
  5. What are the environments available?
  6. Do we have a dedicated testing environment for these APIs?
  7. What are the behaviors of the individual endpoints?
  8. What are the types of testing to be performed?
  9. What are the timelines?
  10. Does it have any other APIs integrated?

Once we have answers to these questions, we will have a good test strategy in hand. But that’s not all; you should learn about a few common API testing challenges and how to overcome them. Only then are we able to begin the testing process. 


API testing challenges


Let’s have a look below at a few common challenges to API testing:


Initial Project Setup

Once the API environments and the necessary infrastructure is ready, you should begin your testing process. If the testing is to be automated, choosing the right framework is also part of that process. Then, based on the timelines, the test cases are drafted, and the resourcing is done accordingly. 

Pro tip: You can better plan the resourcing and estimation in the earlier phases. You can divide the tasks based on the team’s current API testing experience. To plan for automation, first, devise a plan on the feasibility and the percentage of automation.


Lack of Proper/Complete API Documentation

API Documentation is a single source of truth about the API capabilities. So, understanding all the API endpoints, the payload formats/samples, headers, authentication, or any other additional information will be a big challenge. Unfortunately, in most projects, there is no proper documentation. 

Pro tip: Discuss with the stakeholders ahead of time, and ask them to share or work on the proper API documentation. Try to gain knowledge on the list of available API documentation tools so you can suggest to them some options instead of maintaining the API endpoints in a Google doc.


Lack of JSON Knowledge

As you may know, most of the REST APIs use JSON format for the request body and their response. As a tester, we should have a decent level of knowledge of the JSON format and its advantages. Also, it’s good to have basic XML and HTML formats for handling different APIs. With this knowledge, we can avoid basic errors that occur while tweaking the request payloads. It also helps to parse the response easily. 

Pro tip: Before using any payload, it’s advisable to go for any online validator and check the format for any validation issues.


API Sequencing

While testing for your projects, you might need to handle many API endpoints performing different GET, POST, PUT, and DELETE options. So, the Tester should have strong knowledge of the API flows and how the system communicates internally. Based on this understanding, one API call is chained with another. 

Pro tip: Before building your API calls, list your questions and get clarification about the overall flow with the intended stakeholders to avoid confusion. Also, the usage of variables helps with this chaining of requests.


Integration Testing

Other than the original API endpoints to be tested, we might need to communicate with other system APIs. If multiple systems are involved, we must ensure that the data flow is correct between them. This flawless communication is a big challenge since there are multiple dependencies.

Pro tip: Always try to get the bigger picture and stay on top of things. During the analysis phase, try to get information about the other internal or external APIs with which we need to communicate.


Frequent Schema Updation

Based on the business, developers might change the API schema, which might lead to updating the test cases. While there are usually few instances of this, it may be unavoidable. 

Pro tip: Add a few assertions to validate the schema so that you will be notified if that’s not as expected. Connect with the developers frequently.


Test Coverage

Exhaustive testing of APIs is not feasible most of the time. Based on the different types, we must prioritize the APIs’ test cases. 

Pro tip: If there are stringent timelines, 

  1. Focus on the functional testing of the APIs. 
  2. Navigate to the other aspects based on the agreement with the stakeholders. 
  3. Try to implement feasible automation scripts.


Tool Selection Process

For API testing, a plethora of tools are available in the market. Multiple choices leave us in difficult situations. Also, budgeting plays a role here. 

Pro tip: Select tools based on the current team’s expertise, current low/no-code tools, and programming language knowledge. Choose the top two or three tools and do a proper Proof of Concept (PoC), which helps us to select a better tool.



Lack of Technical Knowledge About APIs

If the team is newly built and they have less knowledge about API and API terminologies, the process might be a little tough and lengthy. Sometimes this could lead to inefficient testing. 

Pro tip: Try to hire the appropriate Tester with API knowledge or spend some time learning the API basics. Work closely with the developers and ask questions to help to speed up the learning process.


Requires Coding Knowledge

Most API testing tools/frameworks require decent programming knowledge for API Automation. 

Pro tip: Adopt no/low code API Automation tools, which help the quick setup for the project.


Unstable APIs and Underdeveloped APIs

Not all APIs will behave the same way. Due to external dependencies, some APIs might not be available in the stipulated time. Therefore, a few APIs might behave inconsistently in the initial development phase. 

Pro tip: Don’t wait for the entire API development to be completed. Get the sample API response from the developers and set up a mock server to start writing the assertions. Mock servers will be helpful when the APIs are unstable and you require API sequencing as well.


Exceptional Handling

Handling positive responses is a pretty straightforward scenario. However, the developer might not handle every route properly when it comes to error messages and status codes. 

Pro tip: Testers should have detailed knowledge about the status code and the universal way of handling those scenarios. 



We could make anything happen with proper planning and deeper knowledge of the hurdles Testers face. We believe this blog explained how to prepare for the API Testing process and its everyday challenges. If you plan for the worst, the journey could be smoother. We wish you good luck overcoming the challenges during your API Testing process. Do you think we’re missing anything? Let us know what your challenges are. 

Pricilla Bilavendran

Pricila Bilavendran is a test engineer and a certified mentor, currently at Billennium, as well as an advocate for diversity and inclusion. Her experience with Functional, EDI, ETL, Automation, API testing and Postman is part of what she shares in her workshops, webinars, and writing. A global ambassador for the WomenTech Network, and one of the speakers at its 2023 conference, she can be found on LinkedIn, Twitter, and her blog.