Keycloak and FusionAuth are two popular Customer Identity and Access Management (CIAM) platforms that offer secure login, registration, multi-factor authentication, single sign-on, and customizable communication templates. Both platforms are free with no restrictions on the number of users, making them more cost-effective than other solutions that charge higher fees as user numbers increase. Keycloak is an open-source project built by a community of developers, while FusionAuth is a small, bootstrapped company dedicated to its customers, offering more flexibility and customization options for specific use cases. However, Keycloak requires its users to purchase and migrate to Red Hat's support products to access official support, whereas FusionAuth offers various support options, including 365/24/7 email, chat, and phone support, as well as hosting and managing services. Overall, both platforms cater to different needs, with Keycloak appealing to developers who prefer open-source solutions and FusionAuth offering a more tailored approach for businesses seeking flexibility and customization.