Qapitol QA

Effective Test Coverage in API Testing – Why and How

The growing popularity of microservices, the need for providing a more seamless customer experience and the ease with which companies (within a larger ecosystem) can share data and integrate their offerings to expand their customer base – are fuelling the growth of APIs. 

As per Markets and Markets, the global API management market is estimated to become $13.7 billion by 2027 from $4.5 billion in 2022, at a CAGR of 25 percent. So, the pressing need to develop a robust testing strategy for APIs is justifiable. And one of the key components of this strategy is achieving effective test coverage.

Test coverage measures the percentage of the application code tested. The bigger this number, the greater the amount of the application code tested and validated for all business requirements. Achieving effective test coverage in API testing is particularly important for two reasons:

  1. Greater vulnerability to cyber threats – APIs form the business logic layer in any 3-layered application architecture. Simply put, they facilitate seamless communication and data exchange between different systems. Their easy access to all sensitive data in the database layer makes them highly vulnerable to cyber threats. Hence, validating their build is strong enough to thwart any cyber attack is critical to mitigating related business risks. An exhaustive test coverage validates that all the use cases have been tested and defects detected early in the development cycle.
  2. Defect remediation efficiency over the course of product development – Intuitively, every product team realizes that the longer it takes to detect a defect in an application, the more resources need to be deployed to remediate it (without disrupting the whole application code) and hence greater is the cost involved.

But do you have a clear number on the cost and the answer is often a no? While organisations go all-out to keep all other operational costs in check, very few keep track of the money lost due to insufficient test coverage of their apps and APIs.

But worry not. We have the answers for you today.

In 1996, Capers Jones came up with a study on how the cost of repairing defects increases during different stages in product development and made startling observations that remain true after a couple of decades.


The cost of defect remediation increases to a whopping 640X if the defects go undetected during the testing phase. Imagine your APIs leaking this money because they were not tested thoroughly. 

Could you afford it? No organisation can!

Hence, the need for effective test coverage in API testing to validate them for their functionality, security, performance and reliability.

But suppose you are aiming for effective coverage with manual testing. In that case, you are playing a losing game since the resources and cost involved in manual testing will erode any savings from early defect detection and the fact that it isn’t even scalable.

That is why zero code API testing. And while you may be apprehensive of the limitations in drag and drop features, worry not. We have got your back.

Here is a detailed guide on achieving effective test coverage in API testing with our customised Zero code Framework for you to understand how to tailor zero code API testing to suit your business and testing requirements.

Download your copy here!

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    Gartner, “Market Guide for Application Testing Services”, Jaideep Thyagarajan, Susanne Matson, Gunjan Gupta, Brett Sparks, Akshit Malik, 31 January 2021. GARTNER is a registered trademark and service mark of Gartner, Inc. and/or its affiliates in the U.S. and internationally and is used herein with permission. All rights reserved.

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