FusionAuth is a comprehensive Customer Identity and Access Management (CIAM) platform developed by FusionAuth. It provides authentication, authorization, and user management services for web, mobile, and IoT applications. FusionAuth offers both self-hosted and cloud-based deployment options, supporting scalability for millions of users across thousands of tenants and applications. The platform is designed to be customizable, developer-friendly, and API-first, implementing industry-standard protocols such as OAuth 2.0, OpenID Connect, and SAML v2. FusionAuth can handle authentication needs for applications of various scales, from small projects to large enterprises with hundreds of millions of users.