A sharp exchange lit up X last week. One startup founder suggested AI agents could simply memorize credit card numbers and skip blockchain entirely. Paul Graham pushed back hard. “Because then you have to add card fees,” the Y Combinator cofounder wrote. “Why drag Visa along with us into the future like a software virus?”
The exchange captured a tension now playing out in boardrooms and on-chain dashboards alike. Stablecoins settled more value in 2025 than Visa and Mastercard combined in some measures. Yet the card networks refuse to fade. They absorb the new rails instead.
Visa reported a $7 billion annualized run rate for stablecoin settlements in April 2026. That figure jumped more than 50% from the prior quarter. The company added five blockchains to its pilot. Nine chains now support issuer and acquirer settlements. Visa has expanded from initial USDC tests in 2023 to Solana, Ethereum and beyond.
Mastercard answered with its own moves. The company agreed to acquire BVNK, a London-based stablecoin infrastructure provider, for up to $1.8 billion. The deal, announced in March 2026, gives Mastercard direct control over technology that bridges fiat systems and blockchains across more than 130 countries. “Adding on-chain rails to our network will support speed and programmability for virtually every type of transaction,” said Jorn Lambert, Mastercard’s chief product officer.
These aren’t defensive gestures. Both networks position themselves as orchestrators. An analyst quoted in The Wall Street Journal put it plainly. Visa and Mastercard aim to avoid becoming casualties of stablecoins and the rise of agent-driven commerce.
Cuy Sheffield, who leads crypto efforts at Visa, jumped into the same X debate. He floated the idea of instant on-chain merchant settlement using stablecoins. Such a step could remove one of the disruptors’ clearest advantages: near-zero fees and immediate finality. Visa’s own fees sit around 12 basis points. That sounds low until compared with sub-1 basis point possibilities on blockchain rails.
Merchants still pay 3% to 4% on many credit card transactions. Banks capture most of that. Rewards programs return a sizable share to consumers. This five-sided network — issuers, acquirers, merchants, consumers and the network itself — creates powerful lock-in. Fraud resolution comes built in. Global reach spans countries where local banking rails remain patchy.
But the math shifts when agents optimize for cost. Programmable money lets developers embed rules directly into payments. Settlement happens in seconds rather than days. Cross-border transfers avoid correspondent banks and their fees. A research note from Citrini Research warned that AI agents could systematically bypass card rails to chase lower costs.
Stablecoin transaction volumes already tell part of the story. One report tallied $33 trillion in U.S. financial transactions through stablecoins in 2025. That topped the combined $25.5 trillion processed by Visa and Mastercard. Projections from crypto research firms point to stablecoin volumes potentially hitting $1.5 quadrillion over the next decade. They could surpass card networks between 2031 and 2039 if trends hold. The Motley Fool highlighted these forecasts.
Real-world payment volumes remain smaller but grow fast. Stripe’s Bridge, now owned by the payments giant, saw stablecoin volume reach around $400 billion in 2025. Roughly 60% was B2B. Visa’s stablecoin-linked card programs exceed 160 globally. Partners include Rain, Reap and Bridge. Ryan McInerney, Visa’s CEO, cited these figures during the company’s first-quarter earnings call.
Mastercard pursues a complementary path. It partners with Circle and Paxos for conversion and settlement. Pilots target payouts and merchant acceptance in regions including Eastern Europe, the Middle East and Africa. SoFi plans to offer its SoFiUSD stablecoin as a settlement option across the network. The acquisition of BVNK accelerates infrastructure integration. Clients such as Worldpay, Deel and Flywire already use the platform.
Stablecoin-first ventures push forward too. Augustus, led by a 25-year-old Thiel fellow, raised $40 million and secured a national bank charter from the Office of the Comptroller of the Currency. The firm focuses on programmable money and on-chain banking. MoonPay bought Dflow, a Solana-based platform, in an all-stock deal valued at $100 million. These players target the edges where agents and APIs create new behaviors.
Yet convergence defines the current phase. Stablecoins do not replace card networks outright. They flow through them. Users hold USDC in a wallet. A linked Visa or Mastercard credential lets them spend at millions of merchants without first swapping to fiat. Settlement can occur on-chain. The card brand provides acceptance, fraud tools and consumer protections. The blockchain handles speed and reduced costs.
Rain became a Mastercard Principal Member in early May 2026. The startup issues stablecoin-powered credit and prepaid cards. It now reaches more than 210 countries and regions. Rain also works with Visa. The company explores on-chain settlement for select flows using regulated stablecoins. “Stablecoins are no longer on the fringe of global payments,” the firm stated.
Partnerships multiply. Visa works with WeFi to test stablecoin-backed balances spent through familiar payment methods. AWS teamed with Coinbase and Stripe to let AI agents execute micropayments in USDC. These experiments point toward an agentic future where software conducts commerce at volumes and speeds humans cannot match.
Regulatory tailwinds help. The OCC’s charter for Augustus signals openness. Europe’s MiCA framework provides clarity. U.S. Senate discussions on stablecoin legislation continue. Banks and crypto firms tussle over details such as rewards on stablecoin balances. But momentum favors integration over isolation.
Challenges persist. Interoperability across chains remains imperfect. Custody models differ. Some solutions keep assets on-chain with separate execution layers. Others rely on custodial wallets. Consumer experience still matters. Most people don’t want to manage private keys when buying coffee. The networks that hide complexity while delivering speed and low cost will capture the largest share.
Visa and Mastercard bet they can do exactly that. They extend their infrastructure rather than defend old perimeters. Stablecoin settlement volumes grow inside their systems. Card programs multiply. Acquisitions bring blockchain talent and technology in-house.
Disruptors counter with lower fees and native programmability. They court the developers building agent economies. Paul Graham’s quip resonates there. Yet Visa’s five-year track record with stablecoins shows adaptation. The card giant processed billions in settlements. It supports multiple stablecoins including USDC, PYUSD, USDG and EURC across chains.
The outcome looks less like outright victory for one side. Both networks and blockchain natives gain. Merchants get faster settlement and lower costs in some flows. Consumers access yield on balances that also spend like cash. Agents execute at efficiencies previously impossible.
Still, the incumbents hold structural advantages. Global merchant acceptance didn’t appear overnight. Fraud systems evolved over decades. Trust in dispute resolution runs deep. New technologies introduce fresh risks around smart-contract exploits and regulatory gray zones.
Fortune’s Jeff John Roberts examined this tension in his May 11, 2026 article. He acknowledged Visa’s resilience but placed his bet on the challengers. “The rise of programmable money and blockchain rails means it’s easy to lower transaction fees to well below 1 basis point,” he wrote. New businesses around data and APIs could emerge beyond the card networks’ reach. “When it comes to agentic commerce, we’re still in the first inning.”
That inning stretches longer than many crypto advocates admit. Visa’s $7 billion run rate and Mastercard’s infrastructure purchases demonstrate serious commitment. Stablecoin volumes may eclipse card transaction counts in coming years. But the networks embedding those volumes could capture fees, data and orchestration roles.
The debate on X was civil. The real contest plays out in product road maps, regulatory filings and settlement dashboards. One side doesn’t vanish. It mutates. Visa and Mastercard absorb blockchain rails while stablecoin issuers and infrastructure firms tap into century-old acceptance networks.
Programmable money changes what payments can do. Instant settlement, embedded compliance, automated treasury moves. The companies that combine those capabilities with scale and trust stand to gain most. Right now, that combination looks like a hybrid. Card brands on one layer. Stablecoins powering the rails beneath.
And the agents? They will choose whatever combination delivers the lowest cost and highest reliability. For the moment, that still often routes through Visa or Mastercard rails, even when the money itself lives on-chain. The virus Graham warned about proves remarkably adaptable.
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