Free ACP Payments Module: Accept Payments in Your MCP Server
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Free ACP Payments Module: Accept Payments in Your MCP Server
The ACP Payment Module (published as mcp-commerce) is a free, open source commerce core that lets any MCP server take payments directly inside an AI conversation. It implements the Agentic Commerce Protocol (ACP) checkout API, ships ready-made MCP shopping tools, and charges cards through Stripe, so a customer talking to your tool in Claude, ChatGPT, or any other agent can search your products, build a cart, and pay without ever leaving the chat. You point it at a simple products file, set a Stripe key, and your existing MCP tool becomes a store.
On This Page
What the ACP Payments Module Is
Why Agentic Commerce Changes Checkout
Who This Module Is For
Three Ways to Run It
What Happens During a Sale
Two Payment Modes, One Core
Price Integrity and Security by Default
Architecture at a Glance
Build It Yourself vs Integrate the Module
Requirements, License, and Cost
Getting Started
Technical Reference
Payments and Operations
What the ACP Payments Module Is
MCP (Model Context Protocol) servers give AI assistants tools: search this catalog, look up that account, generate this asset. What they have not had is a clean way to take money. The moment a company wants to sell a Pro license, a credit pack, or a digital product through its MCP tool, it faces a pile of undifferentiated work: cart state, price math, checkout sessions, payment provider integration, webhook verification, idempotency, and a new protocol (ACP) that agent platforms expect merchants to speak. The ACP Payment Module packages all of that as a drop-in library and reference server, free under the Elastic License 2.0, with the source on GitHub.
The design premise is simple: the commerce should ride along with a product and a brand that already exist. This module is built for companies that already run, or are building, an MCP tool and want to charge for something inside it. The shopper already trusts the brand they are talking to, so the usual cold-start trust problem of an unknown storefront never appears. The module deliberately stays out of the way of your business systems. It is not a CRM, not an order database, and not a customer history store. When a payment succeeds, it hands the completed order to your systems through a signed webhook and keeps nothing, which also keeps your compliance surface small.
Everything ships in one TypeScript package named mcp-commerce that runs on Node.js 20 or newer. The commerce logic is a standalone library, and the two network faces over it are thin: an MCP server exposing shopping tools to agents, and an ACP REST API exposing checkout sessions to agent platforms. The same core also serves an ACP product feed so platforms can discover what you sell, in JSONL or CSV format. You can read the protocol background in What Is the Agentic Commerce Protocol, or jump straight to the quickstart.
Why Agentic Commerce Changes Checkout
Traditional ecommerce assumes a human on a website: they browse pages, click a cart icon, and type card details into a form. Agentic commerce assumes an AI assistant acting for that human. The assistant needs machine-readable products, a checkout API it can drive programmatically, and a payment method it can either hand to the human (a hosted payment link) or execute itself with a scoped, pre-authorized token. The Agentic Commerce Protocol is the emerging standard for that interaction, defining how an agent platform creates a checkout session with a merchant, updates it, and completes payment. OpenAI publishes the specification and Stripe provides the matching payment rails, so merchants who speak ACP can appear as buyable inside AI assistants rather than just linkable.
For a small software company this is a meaningful new sales channel. A developer asking an assistant to upgrade their plan, renew a license, or buy more credits is expressing purchase intent at the exact moment the product is in use. The module makes that moment transactable. The conversation that was already happening becomes the checkout, and the sale completes in seconds instead of bouncing the customer to a website where carts go to be abandoned. Our guides on cart abandonment document how much revenue leaks out of every extra step in a traditional checkout, and agentic checkout removes most of those steps entirely.
The protocol itself is young and still in beta, which is exactly why a maintained open source implementation is useful. The module pins a published ACP spec snapshot (API version 2026-04-17), maps its session states, error codes, and headers faithfully, and isolates all of it behind interfaces, so when the spec moves, the surface that changes is small. The ACP endpoints reference documents the exact wire behavior.
Who This Module Is For
The clearest fit is a software company with an existing MCP tool and something digital to sell...