Definition
The Agentic Commerce Protocol (ACP) is an open, Apache-2.0–licensed standard co-developed and maintained by OpenAI and Stripe that defines how buyers, AI agents, and merchants exchange structured information to complete a purchase.
In practice, ACP is implemented through a set of commerce specs that cover product data, checkout session management, and delegated payment tokenization—so an agent can move from “show me options” to “place the order,” while the merchant keeps their existing commerce and payment systems.
How it relates to marketing
ACP matters to marketing because it creates a standardized path for AI-driven discovery → in-conversation checkout (for example, ChatGPT “Instant Checkout”), turning conversational interfaces into a measurable commerce channel.
Marketing-relevant implications typically include:
- A new conversion surface: shoppers can confirm item, shipping, and payment details without leaving the AI interface (where supported). (OpenAI)
- Feed-driven merchandising: product eligibility, availability, and pricing accuracy depend on merchant-provided product feeds (and updates). (OpenAI Developers)
- Merchant-controlled post-purchase: orders, fulfillment, returns, and chargebacks remain with the merchant (the agent is a conduit, not the merchant of record). (OpenAI Developers)
How to calculate
ACP itself is a protocol (so it’s not “calculated”), but teams often track ACP-enabled commerce as a distinct channel with metrics like:
- Agentic conversion rate = ACP orders ÷ ACP shopping sessions
- Checkout completion rate = completed checkout sessions ÷ created checkout sessions
- Offer/availability mismatch rate = (price mismatch + out-of-stock events) ÷ checkout attempts (often tied back to feed freshness) (OpenAI Developers)
- Order acceptance rate = accepted orders ÷ submitted orders (merchants can accept or decline). (OpenAI Developers)
How to utilize
Common ACP usage patterns for merchants (and the marketing/commerce ops teams that support them) include:
- Publish a structured product feed so the AI agent can index and surface products with up-to-date pricing and availability; the spec also includes flags controlling eligibility for discovery and checkout. (OpenAI Developers)
- Implement the Agentic Checkout endpoints to create, update, and complete stateful checkout sessions; responses are expected to return the authoritative cart state, totals, messages, and policy links (e.g., ToS). (OpenAI Developers)
- Integrate delegated payments when needed: the delegated payment spec is designed to securely pass constrained, single-use payment details via the merchant’s PSP/vault, using allowances like max amount and expiry. (OpenAI Developers)
- Keep order state synchronized via order lifecycle events/webhooks so the agent’s UI reflects fulfillment-grade truth. (OpenAI Developers)
(Translation: you’re building a checkout flow that can survive retries, missing addresses, and the occasional agent that asks the same thing twice—politely.)
Compare to similar approaches
| Approach | Primary focus | What it standardizes | Typical implementers | Notes |
|---|---|---|---|---|
| ACP (Agentic Commerce Protocol) | End-to-end agentic commerce | Product feeds, stateful checkout sessions, delegated payment tokenization, order events | Merchants, platforms, PSPs | Open standard maintained by OpenAI + Stripe; used by ChatGPT Instant Checkout. (OpenAI Developers) |
| UCP (Universal Commerce Protocol) | Agent-to-merchant interoperability (broadly similar space) | Business profile + capabilities + checkout flows (implementation varies by spec) | Retailers, platforms | Often discussed as a competing/parallel standard in agentic shopping. (The Verge) |
| AP2 (Agent Payments Protocol) | Agentic payments authorization | Authorization and payment controls for agent-driven payments | Platforms, payment networks, PSPs | Payments-centric rather than full commerce flow. (GitHub) |
| MCP (Model Context Protocol) | Tool access for models | How models call external tools/services | Any tool provider | Not commerce-specific; ACP can coexist with MCP-style tool calling. (OpenAI Developers) |
Best practices
- Treat feed freshness as revenue protection: update product, price, and availability data frequently to reduce mismatches and out-of-stock scenarios. (OpenAI Developers)
- Make checkout endpoints resilient: enforce idempotency keys, return rich state on every response, and support safe retries and conflict handling (e.g., 409 on idempotency conflicts). (OpenAI Developers)
- Operationalize security controls: use TLS (minimum versions as required), validate request signatures, and verify webhook signatures (HMAC) for order events. (OpenAI Developers)
- Plan PCI scope intentionally: ACP separates product feed and checkout specs from cardholder data; delegated payment integrations may affect PCI scope depending on implementation path. (OpenAI Developers)
- Instrument ACP as its own channel: tag ACP traffic/orders and align analytics definitions across commerce, marketing, and finance so attribution arguments can happen in daylight.
Future trends
- Richer carts and fulfillment models: ACP docs note current constraints (for example, single shipping address / one selected shipping option) and anticipate expanded capabilities over time. (OpenAI Developers)
- More PSP and platform adapters: delegated payment patterns (including constrained-use tokens) are positioned to expand beyond early implementations as additional PSPs adopt compatible flows. (OpenAI Developers)
- Standard competition and convergence: expect continued parallel standards (ACP, UCP, payments-focused protocols) with pressure to interoperate across agents and commerce stacks. (The Verge)
Related Terms
- E-commerce
- Agentic commerce
- Agentic Commerce Protocol (ACP)
- Universal Commerce Protocol (UCP)
- Agent Payments Protocol (AP2)
- Agentic Merchant Protocol (AMP)
- Conversational commerce
- Product feed specification
- Checkout session
- Order lifecycle events
- Webhooks
- Delegated payments
- Shared payment token
- Merchant of record (MoR)
- Model Context Protocol (MCP)
- Universal Commerce Protocol (UCP)
- Unified Incentives Protocol (UIP)
References
OpenAI. (2025). Agentic Commerce (ACP) documentation hub. (OpenAI Developers)
OpenAI. (2025). Agentic Checkout Spec. (OpenAI Developers)
OpenAI. (2025). Product Feed Spec. (OpenAI Developers)
OpenAI. (2025). Delegated Payment Spec. (OpenAI Developers)
OpenAI. (2025). Agentic commerce in production (production readiness). (OpenAI Developers)
OpenAI. (2025). Buy it in ChatGPT: Instant Checkout and the Agentic Commerce Protocol. (OpenAI)
Stripe. (2025). Stripe powers Instant Checkout in ChatGPT and releases Agentic Commerce Protocol co-developed with OpenAI (Newsroom). (Stripe)
Stripe. (2025). Build the Agentic Commerce Protocol checkout endpoints (Documentation). (Stripe Docs)
PayPal. (2025). OpenAI and PayPal Team Up to Power Instant Checkout and Agentic Commerce in ChatGPT (Press release). (PayPal Newsroom)
Agentic Commerce Protocol. (2025). Specification repository (GitHub). (GitHub)