Circle’s Agent Stack Backs USDC Payments for AI Services

Circle is developing payment infrastructure for AI agents to buy digital services with USDC, opening a potential use for the stablecoin in automated purchases of API access, data and computing.

Agent Stack products launched May 11. They include Agent Wallets, an Agent Marketplace, a command-line interface and nanopayments powered by Circle Gateway. The tools let agents hold funds, find services and make programmable payments across supported blockchains and payment protocols. Permissions and spending controls are also available.

In the second quarter of 2026, Agent Stack had more than 900 paid services, and USDC settled 99.3% of x402 agent-payment volume. The results did not provide a dollar total for that volume.

An earlier figure put USDC’s share of x402 transaction value at 99.8% as of April 29. That figure covers a different period and measures transaction value, while the second-quarter figure measures agent-payment volume, so the rates are not directly comparable.

Circle’s nanopayment system supports gas-free transfers as small as $0.000001. The x402 activity covers one payment protocol; it does not establish adoption across all AI-agent payments or show how much money moved or whether use was recurring.