Visa and Stripe back the protocol that lets an agent pay a server's price with no login

The purchases in this design are small and internal. An agent researching a market needs information from several paid data sources. Another needs a particular API or a small amount of computing power to finish a task. Instead of someone opening an account or a subscription each time, the agent finds the service and pays only for what it uses ^[13]. The flight is the illustration TheNextWeb leads with. The same piece concedes that giving the agent permission to buy the ticket is the harder problem, because most payment systems were built around a person entering card details and clicking approve ^[20].

x402 is an open protocol Coinbase developed, and it revives HTTP 402, the "Payment Required" status code that has existed for years without being widely used ^[4]. Atul Khekade, co-founder of XDC Network, said "Every internet transaction so far has assumed a person is on the other end of it" ^[7]. He added: "AI Agents are breaking that assumption completely. If software is going to act on our behalf, it needs a way to pay for what it needs without waiting for someone to approve it every time" ^[8]. Discovery, in XDC's version, happens inside XDC's own marketplace, where the agent finds an API and pays per use in USDC ^[10].

What separates the purchases an agent can make now from the ones that still route through a person is unit price. Mastercard launched Agent Pay for Machines in June and described agents continuously buying services from each other in payments worth fractions of a cent ^[3]. At that size the cost of a wrong purchase is below the cost of the review that would have caught it. A metered API call is also repeatable, so the second attempt costs the same as the first.

The demand figures being quoted around all of this are loose. McKinsey estimates AI agents could mediate between $3 trillion and $5 trillion of global consumer commerce by 2030 ^[2]. That is a spread of $2 trillion, with the top of the range about 67 percent above the bottom ^[15]. Gartner expects agentic AI to be built into 33 percent of enterprise software applications by 2028, against less than 1 percent in 2024 ^[1]. That is an increase of at least 33 times in four years ^[16]. Against those, TheNextWeb reports no transaction volume for x402 at all, and notes a gap between the protocol's onchain activity and its ecosystem valuation without putting a number on either side ^[14].

So the strongest adoption evidence on the table is a membership list, and the report names seven of the 40 members without identifying the other 33 ^[6][17]. The list tells a developer which large firms want the plumbing to exist, and it says nothing to an operator about how many paid calls have actually settled this way. The one integration that connects the two worlds is XDC Tech's link to Bridge, a Stripe company, which gives developers infrastructure for moving between fiat currencies and stablecoins ^[11].