AP2 (Agent Payments Protocol)

AP2 (Agent Payments Protocol) is Google’s framework for delegating payment authority from a human principal to an AI agent via structured mandates. AP2 handles the trust and authorization layer — who is allowed to spend, how much, under what conditions — while x402 handles the settlement and plumbing layer. Google built an A2A x402 extension for AP2, confirming the two protocols are complementary, not competing.

Canonical site: Stable402.com (covers the unified agentic payment stack) Cross-references: StableM2M.com, StableKYA.com