Sergey Nechaev and Ilya Shuvalov, community members and software developers at Readymag, use FusionAuth for user authentication, social sign-on, two-factor authentication, and authorization of internal applications. They outsource auth to a separate service with clear structure, reasonable update policies, and good support. The main advantages of FusionAuth include its convenient API, well-prepared documentation, helpful community resources, cost-effectiveness, TypeScript support, and quick deployment time. By using FusionAuth, Readymag saves time and money by outsourcing authentication and reducing the need for custom solutions.