Stablecoins Emerge as Top Payment Rail for AI Agents, Coinbase Says

November 21, 2025 — AI agents are emerging as a new class of crypto users, making autonomous micropayments for data, computing power and online tools, with stablecoins taking an early lead in machine-to-machine transactions. Coinbase’s x402 protocol has processed over 165 million payments totaling $50 million, with roughly 99% settled in USDC.

Immediate Details & Direct Quotes

Coinbase has developed x402, a payment protocol designed specifically for AI agents to purchase services without human intervention. The system functions as a paywall for software: when an agent requests data or a service, the seller responds with a price, the agent pays, and results are released once payment is verified. The name references the “402 Payment Required” HTTP status code.

Lincoln Murr, Coinbase’s head of AI product, told CoinDesk that the primary use case today is machine-to-machine payments from agents to APIs. “Given the velocity of these AI agents and how quickly they move across the internet, we need a standard way for them to pay for things,” Murr said.

The average transaction size is roughly 30 cents, with most payments going to application programming interfaces (APIs) rather than consumer purchases. The majority of transactions occur on Base, Coinbase’s layer two blockchain. Murr estimated that 25% to 30% of transactions may have been generated by users attempting to climb public leaderboards.

Market Context & Reaction

Cloudflare, MoonPay, Visa and Mastercard are all developing competing systems for agentic payments. Cloudflare launched Cloudflare Wallets and cloudflare.pay earlier this month, designing the product to function more like a corporate card than an unrestricted crypto wallet. Operators can deposit money into a main wallet, give agents smaller allowances and set rules around budgets and approved sellers.

Mastercard’s approach uses digital spending vouchers called Verifiable Vouchers, allowing an owner to define what an agent may purchase and its spending limits. The company frames the system as approving “operating boundaries” rather than individual transactions.

“As of mid-2025, x402 moved about $24 million over 30 days in July, roughly what Visa processes in one minute,” Murr said, comparing the current stage to the “Napster/LimeWire era” of agentic payments.

MoonPay’s PayBox, launched July 29, connects to Claude or ChatGPT and stores both card and crypto wallet access. Users can approve purchases with a passkey or allow spending within preset limits.

Background & Historical Context

Stablecoins offer advantages for small, high-frequency payments that card networks struggle to serve economically. Card acceptance costs run 2% to 4%, making microtransactions impractical when fixed processing fees exceed the purchase value. Stablecoins move around the clock, and merchants can cover blockchain fees, meaning agents don’t need to hold additional cryptocurrency for transaction costs.

Stephanie Cohen, Cloudflare’s chief strategy officer, told CoinDesk that “stablecoins are particularly well suited to the kinds of transactions we expect AI agents to make at first, essentially lots of very small, high-frequency payments for things like API calls, data, inference, and content.”

Cards remain entrenched for larger purchases at conventional merchants where buyers expect access to credit, refunds and dispute systems. Mastercard plans to batch small transactions together for settlement while execution happens continuously in real time.

Security concerns remain unresolved. Companies are converging on similar safeguards: capped balances, approved sellers, transaction limits and human approval for sensitive actions. Bryce Ferguson, Turnkey co-founder and CEO, compared current agent controls to early self-driving cars requiring human supervision. “Right now, we’re in that phase for agents,” Ferguson said.

What This Means

Stablecoins have measurable usage in early agentic payment networks, giving them a first-mover advantage as digital services begin charging per request rather than through subscriptions. One agent could make dozens of payments to data providers, AI models and computing services while completing a single task.

Getting money into an agent’s hands remains a significant hurdle. “Getting set up with the wallet is still a massive pain point,” Murr said, noting Coinbase is exploring fiat onramps to solve funding friction.

The future market will likely use multiple payment methods, with agents seeing one price regardless of whether the buyer pays by card, bank account or stablecoin. Crypto does not need to replace cards everywhere to become the de-facto payment method for machines—it just needs to remove setup friction for users.

This is not financial advice. Conduct your own research before making investment decisions.

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