Different paths, same destination: How ACP and AP2 are shaping agent-driven payments innovation

The payments industry has always been defined by shifts in infrastructure: from the emergence of card networks in the 20th century, to mobile wallets in the 2010s, and now, the rise of autonomous agents. Two recent announcements – OpenAI’s Agent Commerce Protocol (ACP) launched with Stripe and Google’s Agent Payments Protocol (AP2) underline how quickly this new chapter is moving from theory into practice.

At first glance, ACP and AP2 might seem similar, and in many ways, they are. Both are open-source protocols, designed to enable AI agents to make purchases on behalf of users. They both push the boundaries of the emerging agentic world, accelerating innovation, and are intended to support multiple payment methods and lower friction in checkout.

Yet, beneath these similarities, a deeper dive reveals that their architectures, positioning, and ambitions diverge in meaningful ways.

OpenAI’s ACP was launched with Stripe (Worldpay have since come onboard) alongside an “Instant Checkout” experience. It is initially only going to be available to U.S. users for one-time purchases from Etsy and Shopify merchants (including brands like Glossier, SKIMS, Spanx, and Vuori). ACP is built to work on top of existing commerce infrastructure: it acts as a secure conduit between ChatGPT agents and merchants, without forcing businesses to rip out their current technical systems or commercial contracts. The focus is very much merchant-centric: enable agents to complete checkouts while preserving merchant control over fulfilment, payments, returns, and the customer relationship.

By contrast, Google’s AP2 is more ambitious in scope. Announced with over 60 collaborators across payments, fintech, infrastructure, and merchant ecosystems, AP2 is designed as a payment-agnostic, open standard to govern agentic commerce across the value chain. It supports both “in-session” payments and “unattended” or delegated transactions (where an agent is authorised in advance to act under conditions), via cryptographically signed mandates and verifiable credentials. Architecturally, AP2 anticipates deeper changes to how agent mandates, identity, and payment provenance are handled, potentially integrating with blockchain or smart contract models

Infrastructure-wise, ACP is a tactical solution built on existing payment rails, while AP2 anticipates more fundamental changes to how agent mandates are handled, potentially aligning with blockchain or smart contract models which are likely to take time to emerge.

These differences also reflect the companies behind them. OpenAI, in partnership with Stripe, is capitalising on its first-mover advantage, deploying a lean, merchant-ready solution to get agentic payments into the wild quickly. Google, by contrast, is taking a broader, more ecosystem-level approach.

In a rapidly evolving AI landscape, several questions remain: will Google’s long-term vision reshape agent-driven commerce, or will OpenAI secure a dominant position simply by being first to market? How will the issuing community keep up with these changes? Could a third player, learning from early deployments, emerge as a fast follower, especially if Apple, Amazon or others step in? How will regulators respond to agent-driven flows, especially around liability, fraud, and transparency?

What is clear is that ACP and AP2 represent the first meaningful steps into a new era of agent-driven payments. Agents are no longer theoretical participants in commerce; they are now active players, capable of not just recommending purchases but completing them. For merchants, developers, and consumers, this is a signal to prepare for a world in which AI-driven transactions become a standard part of the digital payments landscape.