Crypto’s next billion users might be AI agents, and they’re paying with stablecoins

For years, companies like Coinbase and Solana Labs have ruminated about how to onboard the next billion users into crypto.

Those users may soon arrive, but not in the form executives once expected. They won’t be underbanked people in the developing world, or people seeking a way to escape hyperinflation. In fact, the industry’s next big wave of users might not be people at all — they might be software.

AI agents, artificial intelligence software capable of carrying out multi-step tasks, are now transacting on behalf of their users. To perform these tasks, an agent often needs to purchase something.

Crypto and fintech giants alike are rushing in to build the rails — and the money — these agents will use. Coinbase has developed x402, a payment protocol for AI agents, while MoonPay’s PayBox gives agents access to their users’ cards and crypto wallets.

Cloud-computing company Cloudflare is also getting in on the rail-building, rolling out Cloudflare Wallets and cloudflare.pay earlier this month. The infrastructure will enable AI agents to make online purchases within set limits, while also allowing online sellers to see the human identity behind a given agent.

What those agents will pay for these services with is still an open question, and depends on who you ask. In a nutshell, major payments market players aren’t deciding whether machines will lead the next frontier in the sector. They’re competing over what kind of money will be used.

Stablecoins have the strongest position so far in payments designed from scratch for software. Cards remain entrenched for larger purchases at conventional merchants, where buyers expect access to credit, refunds and dispute systems.

Stablecoin issuer Circle is testing $USDC micropayments, Visa and Mastercard are looking to adapt their existing network for agent purchases, and even BitMEX co-founder Arthur Hayes has said he’s coming out of retirement to work on a currency for the agentic economy.

Coinbase said earlier in the year that x402 had processed more than 165 million payments worth a combined $50 million.

The process sees an agent receive a price, send payment and get what it asked for without creating an account or typing in card details. That’s without the involvement of a human, beyond prompting the agent to achieve a task that necessitated that payment.

Lincoln Murr, Coinbase’s head of AI product, told CoinDesk he estimates about 99% of those payments use $USDC. If accurate, that figure gives dollar-denominated stablecoins an early lead in the part of the market where usage can be measured.

“Those guardrails are really what make that autonomy possible,” Cohen said. Inside those limits, the agent could spend without asking its owner to approve each transaction.

Cohen also said various small purchases can be grouped together before recording the combined payment on a blockchain. Batching reduces fees and can be paired with escrow, which keeps the money locked until a seller delivers what the agent bought.

Its planned Monetization Gateway would allow websites to charge for an individual page, dataset or online tool rather than require a subscription.

The system is largely not live yet. Users can claim an identity through cloudflare.pay, but Cohen said funding, withdrawals and wallets for agents are “expected in the coming months.” The Monetization Gateway has been announced but has not been broadly released.

Circle is testing a similar model with $USDC. Its Nanopayments product confirms small payments quickly, then records their combined value on a blockchain later.

MoonPay is pushing the idea closer to consumer-facing agents without committing to a single payment rail through PayBox, launched July 29, which connects to Claude or ChatGPT and stores access to both cards and crypto wallets.

Users can approve each purchase with a passkey or let an agent spend within preset limits. PayBox uses x402 for online services and Visa’s system for card payments, allowing the same agent to handle reservations, travel and shopping alongside crypto transactions.

MoonPay says no single agent or compromised system holds everything needed to move the money. The company has not disclosed adoption figures or the share of payments made with cards versus stablecoins.

Cards aren’t out of the race

While stablecoins might appear to be the obvious choice for agentic payments, card networks aren’t just giving up.

Mastercard’s approach uses a digital spending voucher wherein an owner defines what an agent may buy and how much it can spend. A seller checks those rules, provides the service and claims payment later.

Mastercard calls the product Agent Pay for Machines and the credentials Verifiable Vouchers. Bundling vouchers together would allow the system to avoid sending every tiny transaction through the full card-payment process.

“Execution can happen continuously in real time, while settlement follows a more efficient batched model,” Sapan Mandloi, Mastercard’s executive vice president of tokenization and checkout services, told CoinDesk.

The seller could choose to receive in fiat currency or an accepted stablecoin, meaning the buyer and seller do not need to use the same form of money. From the agent’s perspective, there is simply a price and a spending limit.

“Our view is that agentic commerce will be a multi-rail environment,” Mandloi said. “We see stablecoins as complementary to existing payment systems, not a replacement for them.”

Cards bring one large advantage to the table, as they already work at millions of businesses and are a widely-used payment method.

“Cards remain highly valuable because they provide access to existing acceptance networks, credit, dispute management and familiar user experiences,” Mandloi said.

Mastercard plans to give each agent an identity, record what its owner told it to do and set a budget before the software starts spending.

“This changes the model from approving every individual transaction to approving the operating boundaries within which the agent can act,” Mandloi said. “The agent is then free to execute transactions inside those predefined limits.”

Mastercard’s product is at an earlier stage than x402. The company has opened an Early Access Program but did not provide transaction or adoption figures. Mandloi said the current focus is on validating use cases and testing capabilities along with ecosystem partners.

Meanwhile, banks are testing the same concept on existing payment rails.

In February, DBS and Visa demonstrated an agent purchasing food and drink with DBS/POSB credit and debit cards. Ananya Sen, DBS’s group head of regional consumer products, said the trial showed agent-led payments could be deployed “securely and safely at scale.”

DBS and Visa are now exploring online shopping and travel bookings.

Those purchases look different from a 30-cent API call. They are larger, take place at merchants that already accept cards and come with established systems for refunds and disputes.

When the agent gets it wrong

Moving money is only part of the problem. An agent can misunderstand an instruction, choose the wrong service or obey a malicious prompt even when the payment itself works exactly as designed.

That makes control over the software at least as important as the rail carrying the money.

Coinbase, Cloudflare, Mastercard, MoonPay and wallet company Turnkey are converging on the same first line of defense: restrict the agent before it acts.

Their systems use combinations of capped balances, approved sellers, transaction limits and human approval for sensitive actions.

“Agents need to be granted scoped permissions on a wallet to prevent damages,” Turnkey co-founder and CEO Bryce Ferguson told CoinDesk.

“You can almost think of this like a self-driving car. In the early days, self-driving cars needed somebody with their hands on the steering wheel to make sure nothing went wrong,” he added. “Right now, we're in that phase for agents, and this will evolve over time where we can trust agents to have more and more scope and permissions to take actions without a human in the loop.”

He also drew a dividing line between markets built for software and the ordinary consumer economy.

“Autonomous agents don’t need crypto wallets, strictly speaking,” Ferguson said. “They can use credit cards and bank credentials, but that will likely be for old-school purchases like a pair of shoes or groceries.”

“Crypto is ultimately a much better rail for purchasing a single API call or a single piece of data,” he added.

The size of the transaction also changes how much protection is economical. “For micropayments, mitigating fraud can often cost more than the value of the fraud,” Cloudflare’s Cohen said.

For a payment worth a few cents, a seller’s reputation may matter more than a full dispute process. For a payment worth hundreds or thousands of dollars, the trade-off changes.

“For larger payments, card rails remain a better fit given fraud and other protections,” she said.

Coinbase’s Murr said agent failures are part of the reason x402 is currently focusing on microtransactions.

“If my agent messes up and wastes 10 cents, I’m not going to litigate over that,” Murr said. “However, as we move into larger purchases, we want to add support for escrows and refunds.”

While it’s easier to accept a 10 cent loss, mistakes when booking trips or making large purchases may be more complex and would require recourse for the payer. Crypto firms are eyeing these protections.

Coinbase’s developer documentation describes checkouts where a buyer approves $USDC before the seller collects it, and where completed payments can also be partly or fully refunded.

Cloudflare points to escrow, identity and seller ratings, while Turnkey says agents will eventually need technical proof that a digital service performed the work it was paid to do.

Those systems can prove who authorized an agent, how much it was allowed to spend and whether the seller delivered something. They cannot, however, prove that the agent understood what its owner meant.

Who bears responsibility when the machine follows the rules and still makes the wrong purchase remains unsettled.

An early lead

Stablecoins already have an early lead in the agentic payments race, and lead could grow if digital services begin charging per request rather than through monthly subscriptions. One agent could make dozens of payments to data providers, AI models and computing services while completing a single task.

For now, the market remains far behind its most aggressive predictions. Cloudflare’s wallets are still in development. Mastercard’s solution is in early access, and Turnkey says activity is not yet at scale. MoonPay has not released usage figures, and a meaningful portion of Coinbase’s transaction count may also reflect testing and leaderboard incentives.

There is another basic hurdle in getting money into an agent’s hands in the first place.

“Getting set up with the wallet is still a massive pain point,” Murr said.

The future market for agentic payments will probably use several methods. An agent may see one price and one set of spending rules with the buyer paying by card, bank account or stablecoin and the seller chooses how to receive the money.

Still, stablecoins have more than a theoretical fit. They have measurable usage and a large share of an early network built for software.

Crypto does not need to replace cards everywhere to become the de-facto payment method for machines, it just needs to remove friction for users to first set up their agents.

“To make it frictionless, we're enabling seamless setup guides,” Murr added. “Ultimately, you should just be able to tell your agent, ‘Set up a Coinbase agentic wallet for me,’ and it will go search the internet, download the wallet, and prompt you to sign in via email and fund it with crypto.”

The hardest part remains funding the agent. Coinbase, Murr added, is looking to solve that with a familiar solution: fiat onramps.