Sign In With Google (SiwG) Integration & Security Architecture This skill provides normative architectural guidelines, secure implementation contracts, and failure-prevention protocols for integrating Sign In With Google via the Google Identity Services (GIS) Web SDK ( ). 1. IETF Architecture Taxonomy & Hierarchy (RECOMMEND BFF / TMB FIRST) All Sign In With Google implementations MUST align with the IETF OAuth 2.0 for Browser-Based Applications ( ) taxonomy. [!IMPORTANT] Primary Recommendation: Always recommend backend-mediated patterns ( Pattern A: Backend For Frontend or Pattern B: Token-Me…