Circle Standardizes $USDC Payments for Machine-to-Machine Commerce

Circle has published an official specification for USDC payments within the Machine Payments Protocol (MPP), allowing AI agents and automated services to settle transactions in USDC across various blockchain networks. The specification, posted on paymentauth.org, outlines how USDC payments can be initiated through the MPP challenge-response flow.

The protocol uses a standardized payment interface for agents transacting in USDC across supported EVM chains and Solana, introducing three capabilities: crosschain payment profiles via Circle Gateway, support for USDC-backed stablecoins, and no API key requirement. The specification also adds USDCx, a $USDC-backed stablecoin on Stacks, to the list of assets agents can spend within the MPP framework.

Circle's entry adds USDC as a named method type alongside existing MPP charge specs covering card, EVM, Lightning, Solana, Stellar, and Stripe. The release extends a wave of agentic-commerce infrastructure, with AWS, Coinbase, Mastercard, and Circle itself having recently launched related services.