Stablecoins Lead AI Agent Payments, Coinbase x402 Tops $50M

Stablecoins are pulling ahead as the default payment rail for machine-to-machine transactions driven by artificial intelligence agents. Coinbase said its x402 protocol has processed more than 165 million payments totaling $50 million, with roughly 99% of those using the USDC stablecoin.

Lincoln Murr, Coinbase's head of AI product, estimated that about 99% of the transactions on x402 use USDC. The average transaction is roughly 30 cents, Murr said. That figure underscores why stablecoins may be better suited than traditional card networks for high-frequency digital commerce where individual purchases fall below a dollar.

Most of the activity involves AI agents buying API access, computing power, data or other digital services. The agents make autonomous payments without human approval. Stablecoins operate around the clock, work across borders and avoid the 2% to 4% fees Coinbase estimates card networks charge.

Traditional card networks are not giving up. Mastercard is building Agent Pay for Machines, while Visa has tested agent-led purchases with DBS. Cards still offer established merchant acceptance, credit lines, refunds and dispute protections that matter for larger transactions like travel or shopping.

The emerging payment ecosystem will likely mix rails. Stablecoins could dominate micropayments between software systems, while cards stay preferred for higher-value consumer purchases. For crypto companies, the opportunity does not require replacing cards entirely. If machines become a major source of payment volume, stablecoins could emerge as one of crypto's most important user groups.

Mastercard, for its part, is also testing stablecoin compliance tools. The company recently worked with Borderless.xyz on a single-audit approach for stablecoin issuers.