API vs. UI Testing: Which One Should You Pick

Darshit Shah
2 min readJun 15, 2024


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Whether to focus on API testing or UI testing depends on your project requirements, goals, and constraints. Here are some considerations to help you decide:

API Testing:

Early Testing: API testing can be performed early in the development lifecycle, even before the UI is fully developed. This can help in identifying issues early and speeding up the development process.

Efficiency: API testing is generally faster and more efficient than UI testing because APIs are more stable and have fewer changes compared to the UI.

Integration Testing: APIs are crucial for integrating different components of a system. Testing APIs ensures that these integrations work correctly.

Automation: API testing is highly amenable to automation, which can further increase efficiency and reliability.

UI Testing:

User Experience: UI testing ensures that the application’s user interface functions correctly and provides a good user experience.

Visual Validation: UI testing includes visual validation, ensuring that the UI elements are displayed correctly and are visually appealing.

End-to-End Testing: UI testing allows you to test the entire application workflow, including interactions between different components.

Real-User Simulation: UI testing simulates real-user interactions, providing a more realistic testing scenario compared to API testing.

Choosing Between API and UI Testing:

Project Stage: In the early stages of development, focusing on API testing can be more beneficial. As the project progresses and the UI becomes more stable, you can shift focus to UI testing.

Critical Functionality: If your application’s critical functionality is exposed through APIs, prioritizing API testing is essential. However, if the UI is the primary interaction point for users, UI testing should be a priority.

Resource Constraints: Consider your team’s expertise and available resources. If you have more experience or resources in one area (API or UI testing), it may make sense to prioritize that.

Comprehensive Testing: For thorough testing, a combination of API and UI testing is recommended. API testing ensures the functionality of the backend, while UI testing ensures a good user experience.

In conclusion, the choice between API and UI testing depends on various factors, and a balanced approach that includes both types of testing is often ideal for ensuring the overall quality of your application.

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Darshit Shah
Senior Lead QA Engineer
Portfolio | LinkedIn



Darshit Shah

Hello! I’m Darshit Shah - ISTQB Certified Software QA Engineer with 13+ years of experience. I believe that by sharing our stories, we can grow together.