The Blockchain Winning the AI Payments Race Isn't the One That Built It

For the first time since AI agents began making payments to each other on blockchain networks, the volume of genuine transactions has surpassed its previous peak — and the network now leading that growth is not the one that pioneered it. As Sandmark's latest analysis in its seven-part Agentic Finance series shows, Polygon has just overtaken Coinbase's Base network in real dollar volume, in a shift that reveals as much about incentive design and distribution as it does about blockchain technology itself.

To understand why this matters, it helps to understand what AI agent payments actually are. Agentic finance refers to software agents, or autonomous programmes, that hold funds and spend them without a human approving each transaction. That creates specific demands on the underlying network: speed and low-cost matter far more than they do for human users, because a system making thousands of small payments a day cannot absorb fees or delays that a person might not notice. Coinbase's Base network built the foundation for this activity and has processed most genuine transactions since the market began in late 2025. But the data, once cleaned of artificial activity, where operators essentially pay themselves to inflate transaction counts, tells a more complicated story. Of the 215 million transactions and $96 million in volume recorded since October 2025, more than a third turns out to be fake. After stripping that out, the real market is considerably smaller but also considerably more interesting: July's adjusted volume of $32 million was nearly double the combined genuine volume of the six months prior, and the average payment value has risen from six cents in January to nearly two dollars — a shift from near-worthless test transactions toward payments that resemble real economic activity.

Polygon's emergence at the top of this ranking is striking and, on closer examination, partially explained. The network went from recording essentially no agent-payment volume between March and May to capturing 88% of the entire market's volume in July. The surge appears real rather than gamed, but the consistency of the daily transaction pattern points toward one large automated workflow rather than broad organic adoption. Polygon also launched a fee-refund programme for intermediaries routing agent payments, meaning a portion of the surge is actively subsidised. Base, by contrast, has built its position on genuine distribution advantages: a payment standard that embeds a payment step directly into ordinary web requests, deep integration with Coinbase's wallet infrastructure, and strong access to the dollar-denominated stablecoin that accounts for virtually all settlement in this market. Neither chain scores best on raw technical metrics — that distinction belongs to networks like Avalanche and Solana — but technical superiority matters less than having the wallets, tools and developer relationships that agents already use.

The broader market context is important for investors reading this trend. Agent payments currently represent just 0.11% of total activity across the seven networks studied, and almost all settlement happens in Circle's USDC stablecoin rather than in any blockchain's native token. That means the entities capturing value today are primarily those controlling wallet infrastructure and stablecoin access, not necessarily the crypto assets securing the underlying networks. The longer-term opportunity, if it materialises, may be more relevant for smaller, more concentrated networks whose entire economic case rests on this kind of activity.