Author: Ben Harvey

Translation: Deep Tide TechFlow

Deep Tide Summary: A year ago, machine-to-machine payments were just a concept. Now Coinbase, Stripe, Google, and Visa have deployed four competitive architectures. AI Agents have completed 176 million transactions, settling $73 million, while traditional giants have spent $8 billion on acquisitions to secure their positions. This is not a future narrative, but a transformation of payment infrastructure that is happening now—whoever controls the most layers takes the most value.

A year ago, machine-to-machine payments were merely a concept. Now four competitive payment architectures are live, backed by some of the biggest tech companies: Coinbase, Stripe, Google, Visa, and American Express. AI Agents have settled over $73 million across 176 million transactions, and traditional giants have invested over $8 billion in acquisitions to capture positions in this new payment stack.

This report is prepared by Keyrock in collaboration with Coinbase and Tempo, studying how this payment stack is assembled, whether the economic model holds, and what obstacles it faces.

Protocols are not competing, but stacking

In September 2024, if you want AI Agents to pay, there will essentially be one insecure option. After 12 months, four architectures are in place, backed by some of the largest companies in the tech sector.

Coinbase has built x402, a crypto-native protocol that turns stablecoin wallets into universal API keys. Stripe and Tempo launched MPP, a payment method-agnostic standard that handles credit cards, cryptocurrencies, and the Lightning Network through a single HTTP process. Google assembled AP2, an authorization layer that allows users to delegate payment rights to Agents via crypto authorizations. Visa expanded existing credit card rails to offer AI-ready tokenized credentials.

What most reports overlook is that these four solutions are not in pure competition. There is indeed overlap at the protocol layer, but the more important dynamic is that they are being assembled into a payment stack. We believe the right question is not "Which protocol will win?" but "Which companies control the most layers, hence capturing the most value?"

The $0.30 Wall

Among the 176 million x402 payments to date, the median transaction amount is between $0.01 and $0.10, with 76% of activities below the $0.30 credit card fee threshold. This figure essentially illustrates why traditional payment rails cannot service this market. A fixed processing fee of approximately 30 cents makes micro payments unprofitable. An Agent paying 3 cents for weather API calls cannot route through Visa.

Layer 2 stablecoin settlement costs $0.0001. For Agents, this means blockchain rails are a necessity.

Dominance of a Single Stablecoin

Of the 176 million payments, 98.6% were settled using USDC. Stablecoins have practically defaulted by winning the settlement layer of machine commerce; they are the only tools that can handle small transactions without the economic model collapsing.

This concentration represents both validation and vulnerability. It validates Circle's positioning as the default settlement asset but also means that the entire Agent payment ecosystem relies on the reserve management, regulatory status, and technological infrastructure of a single stablecoin issuer. No one in the industry discusses this openly. We believe they should.

Vertical Integration Competition

Coinbase and Stripe each cover five layers of the emerging payment stack. Coinbase controls the settlement layer (Base), wallets (Agentic Wallets), routing (internal infrastructure), payment protocol (x402), and governance (as a partner in AP2). Stripe forms a mirrored layout through Tempo (settlement), Privy (wallet), Bridge (routing, via an $1.1 billion acquisition), MPP (protocol), and its compliance infrastructure.

In the past 12 months, traditional giants have invested over $8 billion in acquisitions to fill in gaps in payment stack coverage. Capital One acquired Brex for $5.15 billion, Mastercard spent $1.8 billion to acquire BVNK, and Stripe acquired Bridge. These are all foundational integration moves from companies that view machine payments as an essential business that must expand.

From Robotic Activity to Agent Commerce

The machine economy has arrived. It just hasn’t started doing business yet. But the signals are clear: AI Agents account for 37% of all Safe transactions on the Gnosis Chain, peaking at over 75%. Coinbase has deployed tens of thousands of Agents equipped with built-in safeguards. Over 104,000 Agents are registered across 15 or more directories and registries.

The transition from exploitative robotic activity to productive Agent commerce is underway. The payment infrastructure studied in this report is what makes all this possible.

Regulations are Constraints

MiCA, the GENIUS Act, and the EU AI Act will all reach the execution phase within weeks of each other in 2026. None of them addresses autonomous machine-to-machine transactions. This is not a future issue; it is a present issue unfolding in real-time with real capital at stake.

What Happens Next

The market is moving toward greater Agent autonomy, but we believe the pace will not be set by technology—technology is fundamentally ready. Instead, the pace will be determined by the trust infrastructure that makes this all safe. The vision of a completely permissionless scenario is theoretically appealing, but it assumes a level of AI reliability that does not yet exist. Before Agents stop the illusion, they may not be able to access user funds unsupervised.

We believe that the bottom-up argument presents the most compelling framework for what will happen next. Crypto rails have effectively defaulted to winning micro payments. As transaction volumes grow and trust infrastructure matures, larger transaction amounts will migrate on-chain. The question is not whether machine-native payments can scale but how quickly the trust layer can catch up with the settlement layer.

This article is a summary of the core findings of the research. The complete report delves into the data, including protocol architecture analysis, insights from interviews with Coinbase and Tempo, transaction economic modeling, and the regulatory landscape.