As agents move from answering to transacting, they need to pay — for the products they buy in agentic commerce, and for the APIs and data they consume. Agentic payment protocols provide the authorization and settlement rails to do it safely and programmatically.
The payment rails are dominated by large players (Coinbase, Google, Visa, Mastercard, Stripe). For builders, the open opportunity is the surrounding layer: readiness tooling, monitoring, discovery and education.
Not necessarily. x402 commonly uses stablecoins, but agent-payment authorization (AP2) and card-network schemes (Visa, Mastercard) also support fiat rails. The common thread is programmatic, agent-initiated payment.