FusionAuth is a key component of larger applications, offering simple and secure authentication that can be integrated with various platforms, including JavaScript SPAs, mobile apps, and APIs through OpenID Connect, SAML, or HTTP APIs. The company has developed software development kits (SDKs) for JavaScript frameworks such as Angular, React, and Vue, which provide pre-built functionalities like login, logout, and user registration, enhancing ease of integration. SDKs differ from client libraries in that they offer abstracted functionality without needing an API key and are tailored for specific FusionAuth applications. FusionAuth emphasizes security and functionality by using browser redirects to handle sensitive user credentials, thus reducing the application's exposure to potential vulnerabilities. This approach allows applications to leverage FusionAuth's extensive authentication workflows, including features like MFA and social sign-on, while maintaining a customizable look and feel for hosted login pages. The use of server-side components ensures secure token storage and management, and while direct API interaction is possible, it is discouraged due to security considerations.