ACP — Agentic Commerce Protocol

“An open standard for programmatic commerce flows between buyers, AI agents, and businesses.”

What Is ACP

ACP (Agentic Commerce Protocol) is an open standard created by Stripe that defines the protocol for programmatic commerce interactions between buyers, AI agents, and merchants. OpenAI ChatGPT is the first implementer of ACP. ACP is not a single API. It consists of two independent systems:

System	Direction	Hosted By	Purpose
Product Feed	Merchant to OpenAI	OpenAI platform	Product data synchronization
Agentic Checkout	AI agent to Merchant	Merchant-hosted	Checkout, payment, orders

Protocol Status: Beta (partner approval required) Spec Version History:

2025-09-29 (initial release)
2025-12-12 (fulfillment capabilities)
2026-01-16 (capability negotiation)
2026-01-30 (extensions, discounts, payment processors) — current latest

Official Resources:

Open specification: agenticcommerce.dev
OpenAI merchant docs: developers.openai.com/commerce
GitHub: github.com/agentic-commerce-protocol
Contact: acp@stripe.com

The Two Systems of ACP

System 1: Product Feed (Product Data Sync)

Merchants push product catalog data to the OpenAI platform. There are two methods:

Method	Format	Use Case
SFTP File Upload	Parquet (zstd) / jsonl.gz / csv.gz / tsv.gz	Daily full catalog snapshots
REST API	JSON	Real-time incremental updates during the day

Best Practice: Daily SFTP full sync + API real-time pushes for changes (prices, inventory, promotions).

System 2: Agentic Checkout (Transaction Processing)

Merchants implement 5 API endpoints on their own servers. AI agents call these endpoints to complete transactions when a user confirms a purchase:

POST   /checkout_sessions            Create a checkout session
GET    /checkout_sessions/:id        Query session status
POST   /checkout_sessions/:id        Update session (shipping address, buyer info, etc.)
POST   /checkout_sessions/:id/complete  Complete payment
POST   /checkout_sessions/:id/cancel    Cancel session

Payment credentials are securely transmitted through the Delegate Payment API (hosted by Stripe) — merchants never touch raw card numbers.

ACP vs. UCP Comparison

Dimension	ACP	UCP
Created By	Stripe	Google with Shopify and others
First Implementer	OpenAI ChatGPT	Multiple platforms
Architecture	Merchant pushes data + merchant builds endpoints	Merchant builds API endpoints
Payment	Delegate Payment (vault token)	Payment Token Exchange
Current Status	Beta (application required)	Open
Coverage	Product discovery + checkout + payment	Checkout + identity + orders + payment
Ecosystem	ChatGPT ecosystem	Cross-platform / cross-AI

Merchant Onboarding Flow

Apply for partner status — Submit an application at chatgpt.com/merchants
Get approved — Stripe/OpenAI reviews merchant qualifications
Configure SFTP — Set up the file upload channel
Prepare product data — Format your catalog per the Product object specification
Implement Checkout endpoints — Deploy 5 API endpoints on your server
Integrate Delegate Payment — Connect to Stripe’s payment delegation API
Test and launch — Validate with a small batch, then go live at full scale

Chapter Directory (8 Chapters)

Part I: Core Concepts

ACP Core Concepts — Protocol architecture, four-party model, data flow
Product Data Format — Product/Variant objects, pricing (minor units), media, availability

Part II: Data Synchronization

File Upload Integration — SFTP specifications, sharding strategy, Feed Header
REST API Integration — Feeds/Products/Promotions endpoints, authentication, idempotency

Part III: Transaction Capabilities

Promotions Management — Promotion objects, discount types, active periods

Part IV: Quality and Operations

Data Quality Best Practices — ID stability, URL encoding, description formats, prohibited content
Testing and Validation — Small-batch validation, data compliance checks
Frequently Asked Questions — Common questions during onboarding

ACP is currently in Beta and requires partner approval. This book is based on ACP spec version 2026-01-30 and the OpenAI Commerce documentation. For the latest onboarding policies, visit agenticcommerce.dev.

UCP case studies and extension mechanisms ACP protocol architecture and core concepts

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Learning Paths

Getting Started with AI Commerce

OTR Open Trust Registry

UCP Universal Commerce Protocol