Published Paper Details:

Application Programming Interfaces (APIs) are important components of modern software systems that enable communication between different applications. APIs use parameters in requests to retrieve customized data and perform specific operations. However, changes in request parameters can significantly affect response accuracy and system performance. This research investigates the impact of API parameter variation using different test cases such as valid parameters, missing parameters, invalid parameters, unnecessary extra parameters, and large input values. Experimental testing was performed on REST APIs using standard API testing tools. Metrics such as response time, error rate, status code, and output correctness were analyzed. The results indicate that valid parameters provide the highest efficiency and most accurate responses, while incorrect or excessive parameters increase processing time and error frequency. This study highlights the importance of parameter validation and optimized request design for reliable API development.