Amazon Cognito User Pools core configuration and management
Cognito Lambda Triggers: Pre Sign-up, Post Confirmation, Pre Authentication, Custom Message, Define/Create/Verify Auth Challenge — this is the specialized center of the role
OAuth 2.0 / OpenID Connect (OIDC)
JWT (JSON Web Tokens)
AWS Lambda
C# / .NET or TypeScript / Node.js — proficiency in at least one, since the role is language-adaptable