Yes, it is common and highly beneficial to integrate third-party APIs or services into web apps. Third-party APIs enable web apps to access external functionalities, data, or services, expanding their capabilities without the need to build everything from scratch. This integration can enhance features, offer real-time data, and improve user experiences. Examples include social media logins, payment gateways, mapping services, and data analytics tools. Developers can leverage a wide range of APIs to save time and resources while providing valuable functionality to web app users.