The article provides a comprehensive analysis of the differences between web, hybrid, and native mobile applications, focusing on their development, performance, cost, and testing methodologies. Web apps are described as responsive websites that operate via browsers without needing installation, making them cost-effective and easy to maintain. Native apps, built for specific platforms, provide superior performance and are accessible through app stores but require more resources. Hybrid apps merge features of both web and native apps, offering flexibility in code reuse across multiple platforms. The article also discusses popular development frameworks—such as Ruby on Rails, Django, and AngularJS for web apps, and React Native, Flutter, and Xamarin for mobile apps—and highlights testing tools like Selenium for web and Appium and Espresso for mobile testing. It underscores the importance of testing in ensuring app performance and reliability, with platforms like LambdaTest providing extensive mobile app testing services.