Every major card network has signed on to a payment standard built so that software can pay software without a human involved.
The Linux Foundation said Tuesday that the x402 Foundation is now operating under formal governance with 40 members, and that Coinbase's contribution of the protocol is complete.
Premier members include Ripple, Visa, Mastercard, American Express, Stripe, Adyen, Fiserv, Shopify, Google, Amazon Web Services and Cloudflare, alongside Circle, MoonPay and the Solana and Stellar foundations.
The protocol fills in a thirty-year-old loose end. When the web's architects wrote the rules for how browsers and servers talk to each other, they set aside a response code numbered ‘402’ and labeled it "Payment Required," expecting someone would eventually build payments into the web itself.
Card fees made charging a fraction of a cent pointless, so the web eventually monetized through ads, subscriptions and API keys instead, and 402 sat unused.
Coinbase, among others, filled that gap in May 2025. Under x402, a server that wants payment answers a request with a 402 and a price. The client signs a stablecoin transfer, usually USDC, resends the request with the payment attached, and gets the data. The exchange takes seconds and needs no account, no card, and no prior relationship between the two sides.
That is why the AI industry cares. An autonomous agent cannot open a bank account, pass a credit check or sign a SaaS contract, but can sign a transaction. Google has wired x402 into its own agent payments protocol, and Cloudflare ships it in its agent toolkit.
The announcement included no usage figures, though x402 publishes them on its own homepage. The protocol handled about 75 million transactions over the past 30 days, or roughly 29 every second, moving about $24 million between some 94,000 buyers and 22,000 sellers.
That works out to an average payment of about 32 cents, meaning the machine-to-machine thesis works as designed, as no card network can process a such small charges profitably.
Still, $24 million a month is a fraction of what any of x402's premier members move in a day.
Seperately, onchain data provider DefiLlama tracks a metric it labels DEX volume for x402, which reached nearly $970,000 in a single day on Dec. 3 and has fallen steadily since, coming in at just about $16,000 on July 13 and roughly $572,000 across the past 30 days.