SSO Integration for Web and Mobile

I'm looking for an experienced developer to implement SSO (Single Sign-On) functionality for both our web and mobile applications. Key Requirements: - Initial focus on integration with Microsoft Entra ID, with potential expansion to other identity providers (e.g., Google, Facebook)... (Budget: £250 - £750 GBP, Jobs: Android, C# Programming, Mobile App Development, OAuth, PHP, Security, Web Application, Web Development)