- Runs it
- Projects
- 8
- Official
- 1
- Stars checked
- 2026-11-08
- Spec
- official
AP2 SDKs and Agent Payment Tools: 8 open-source projects compared
Build agent checkout on the Agent Payments Protocol. Compare 8 open-source AP2 SDKs, samples and tools, starting with the official reference implementation.
Compare AP2 projects
These 8 open-source projects implement or support AP2. 1 are maintained by the official project and the rest by the community. Sort by stars or recent activity, or filter by type. These projects are listed from public GitHub data and are not scanned by AgenticMart.
Lucid Agents
Agent commerce SDK that includes AP2 role metadata in discovery
Sardis
SDKs and policy layer for agent payments using AP2 mandate chains
Stars and activity checked 2026-11-08. These projects are listed from public GitHub data and are not scanned by AgenticMart. Built one? List it free now, paid selling opens soon.
What is AP2?
AP2 (Agent Payments Protocol) is an open protocol for payments made by AI agents. It extends the Agent2Agent protocol and integrates with the Universal Commerce Protocol. The current version supports credit and debit card pull payments, with e-wallets, real-time bank transfers and digital currencies on its roadmap.
AP2 vs x402: what is the difference
AP2 is about proving what a user authorized, and x402 is a way to make the payment over HTTP. AP2 is designed to work with both cards and stablecoins, and its sample scenarios include x402 payments. The a2a-x402 project, listed below, combines A2A with x402, and its maintainers plan to align it with AP2 over time. New to MCP? Read what an MCP server is.
What an AP2 message looks like
This is the signed content of a closed AP2 Payment Mandate, which authorizes one specific payment of 199.00 USD to one merchant with one payment instrument. In the spec it travels inside an SD-JWT as a selectively disclosed claim, which is left out here.
{
"vct": "mandate.payment.1",
"transaction_id": "NivWhuqfzcvZNapvIEJ2-3tsdQLkiuIcye2g46WVgX8",
"payee": {
"id": "merchant_1",
"name": "Demo Merchant",
"website": "https://demo-merchant.example"
},
"payment_amount": {
"amount": 19900,
"currency": "USD"
},
"payment_instrument": {
"id": "stub",
"type": "card",
"description": "Card ••••4242"
}
}From the official specification, checked 2026-11-12.
AP2 questions
What is the AP2 protocol?
AP2, the Agent Payments Protocol, is an open protocol for payments made by AI agents. It deals with authorization, authenticity and accountability when a person is not clicking the buy button themselves. It works as an extension of the A2A protocol and is also available as an extension for the Universal Commerce Protocol.
AP2 vs x402: what is the difference?
AP2 is about proving what a user authorized, and x402 is a way to make the payment over HTTP. AP2 is designed to work with both cards and stablecoins, and its sample scenarios include x402 payments. The a2a-x402 project, listed below, combines A2A with x402, and its maintainers plan to align it with AP2 over time.
What payment methods does AP2 support?
As of November 2026, the initial version of AP2 supports pull payments such as credit and debit cards. E-wallets, push payments such as UPI and PIX, and digital currencies are on its roadmap. Its samples also include x402 stablecoin scenarios.
How do I get started with AP2?
Clone the AP2 repository and run one of its sample scenarios with the run.sh script in that scenario's folder. The Python samples need Python 3.11 or higher, the uv package manager and a Google API key or Vertex AI credentials. They use Google's Agent Development Kit and Gemini, but the protocol does not require either.
Who created AP2?
Google created AP2 as an open source project. As of November 2026, the AP2 site says standardization continues in FIDO Alliance working groups, while code and documentation remain on GitHub.
What is the current status of AP2?
As of November 2026, the AP2 site refers to a v0.2 release, and the protocol is still evolving. A PyPI package has not been published yet, and an SDK and MCP server are in development with no release date given.
Does AP2 replace A2A or MCP?
No, AP2 does not replace A2A or MCP, because it adds payment rules for agents and is built as an extension of A2A. As of November 2026, the AP2 FAQ says an MCP server is still in development, and the site describes MCP support in less detail than A2A.