What is Being Tested?
- API Security
- Authentication on endpoint
- Performance of API (eg. Time duration for retrieving the data)
- The behavior of API with invalid requests
- Output parameters
- Status codes, response body, the response by request parameters
- All possible combinations of input
Benefits of API Testing
1. Security
In order to find vulnerabilities, functional testing alone isn't enough. Many security-related issues are also covered in API tests.
2. Cost Effective
By detecting certain bugs at the beginning of project development, we can avoid the expensive bug-fixing cost at the time of release. If we go for an API Testing framework, we can reduce the manual testing and even some front-end testing.
3. Testing at early stage
Before starting work on the front end of the application, API testing can be completed simultaneously with the back-end development, allowing you to check the business logic and overall state of the application. This helps to detect certain bugs at the beginning of project development before they become a more serious problem during GUI testing.
4. Swift Feedback
It may be hard to get instant feedback from functional GUI tests. However, it is much easier to maintain automated API tests than browser tests.
For example, End-to-End testing takes too much time, while API testing can be done after some changes take place in business logic. So we can let the developers know about the latest bugs and the regression at an early stage.
5. Easy Integration
API testing supports third-party integrations, which means there is a possibility to test the third-party services used in the API question. This way, we can ensure the proper working of the API and its interaction with third-party applications. Sending requests properly and receiving corresponding data are included in this interaction. This entire process is known as Acceptance testing. Along with that, if third-party services have a user interface, then we can provide the integration of functional GUI testing.
6. Independent Interface
API testing provides access to applications without a user interface. They are considered the best solution for applications because they don't require the user interface to be tested before front-end development starts.