What does Not documented mean?

Not documented means the page checked for that cell does not state the fact. The cell still links that page and the day it was read. It is not a claim that the fact is false.

Does the use selector pick a protocol?

No. It marks the columns whose cited pages describe that job. The other visible columns stay in the table. The mark is not a ranking.

Where are AP2 and L402?

Both are listings in this directory, so the page can show them as extra columns. The default HTML shows x402, MPP, and ACP. The JSON file includes all five.

Where is the machine readable comparison?

GET /data/agent-payment-protocols.json. The file includes every column, the cited sources, and the as of dates. The HTML table shows the columns named in the page URL.

Why is there no x402 volume on this page?

This page does not quote an x402 volume. The measurement page lists each public figure with its source and the day it was read.

Tool

Agent payment protocols

x402 is an HTTP 402 standard for paying a request, and its site says stablecoins are the primary case. MPP is an HTTP 402 protocol for an agent to pay an API with a card, a stablecoin, or another rail. ACP is a checkout standard for an agent to complete a purchase with a business.

Last verified 2026-10-22

Agent payment protocols JSON · How x402 volume is measured · Protocol compatibility

Stripe's ACP page describes checkout sessions for an agent to complete a purchase with a business. AP2's site describes a checkout mandate and a payment mandate. The x402, MPP, and L402 pages cited here describe HTTP 402 payment for a request. Marking a column does not rank it.

Agent payment protocols compared by cited page
Field	x402	Machine Payments Protocol	Agentic Commerce Protocol Marked for this use	AP2 Marked for this use	L402
Who governs it	The Linux Foundation announcement on 14 July 2026 says Coinbase contributed the protocol and the x402 Foundation stewards it. Linux Foundation announcement of the x402 Foundation, 14 July 2026 As of 2026-10-22	The governance page says MPP is co-authored by Tempo and Stripe. It says the core specification is submitted to the IETF, and that each payment method is maintained by the rail behind it. MPP governance As of 2026-10-22	The repository README says OpenAI and Stripe maintain the specification. Agentic Commerce Protocol repository As of 2026-10-22 Stripe's documentation says the protocol was created by Stripe, OpenAI, and Meta. Stripe documentation for the Agentic Commerce Protocol As of 2026-10-22	The site says standardization continues in the FIDO Alliance Agentic Authentication and Payments technical working groups. The public repository hosts the current specification. AP2 protocol documentation As of 2026-10-22	Lightning Labs publishes the L402 documentation. Aperture is described there as an implementation. Lightning Labs L402 documentation As of 2026-10-22
Layer	HTTP 402. The x402.org page says a request without payment receives HTTP 402, and the client pays and retries. x402 site As of 2026-10-22 The Coinbase how it works page says this is for per request payments without a checkout page, a subscription, or a separate billing integration. Coinbase documentation for how x402 works As of 2026-10-22	HTTP 402. The FAQ says MPP and x402 both use HTTP 402 to signal that a request requires payment. MPP FAQ As of 2026-10-22 Stripe's documentation says the server returns HTTP 402, the agent authorizes the payment, retries the request, and receives a receipt. Stripe documentation for MPP As of 2026-10-22 The session intent page says a session pays for many requests, streamed chunks, or metered units without a separate settlement for each one. It says to use the subscription intent when access renews at a fixed amount. MPP session intent As of 2026-10-22	Checkout. Stripe's documentation says ACP defines checkout sessions, cart and feed, delegated payment, orders, and webhooks. Stripe documentation for the Agentic Commerce Protocol As of 2026-10-22	Checkout. A checkout mandate captures the cart negotiated between an agent and a merchant. A payment mandate authorizes payment against a payment instrument. AP2 protocol documentation As of 2026-10-22 The site says AP2 is an extension for A2A and for the Universal Commerce Protocol, and also an open extension for A2A and MCP. AP2 protocol documentation As of 2026-10-22	HTTP 402. The server answers HTTP 402 with a token bound to a Lightning invoice. The client pays, then presents the preimage. Lightning Labs L402 documentation As of 2026-10-22
Settlement rail	The x402.org FAQ says stablecoin payments are the primary use case, and that the protocol is extensible to traditional payment methods. x402 site As of 2026-10-22 The same FAQ says x402 supports EVM compatible chains, Solana, and more. x402 site As of 2026-10-22 The Linux Foundation announcement says payment types range from traditional cards to stablecoins. Linux Foundation announcement of the x402 Foundation, 14 July 2026 As of 2026-10-22	The FAQ says Tempo stablecoin payments, card payments through Card or Stripe, and Lightning payments are in production. MPP FAQ As of 2026-10-22 The same FAQ says the protocol works with any payment rail, and that anyone can build a custom payment method. MPP FAQ As of 2026-10-22 Stripe's documentation describes authorization with a card or a stablecoin. Stripe documentation for MPP As of 2026-10-22	The delegate payment reference describes a card payment method and an allowance with a currency code. ACP delegate payment As of 2026-10-22 Not documented as of 2026-10-22. Stripe's ACP page describes delegated payment tokens and does not name one settlement rail such as a stablecoin, a card network, or fiat. Stripe documentation for the Agentic Commerce Protocol As of 2026-10-22	Credit and debit cards in the initial version. The page calls these common pull payment methods. AP2 protocol documentation As of 2026-10-22 Not documented as of 2026-10-22. Stablecoin and Lightning are not named as current rails. The same page puts real time bank transfers and digital currencies on a roadmap. AP2 protocol documentation As of 2026-10-22	Lightning. The token commits to a Lightning invoice by its payment hash. Lightning Labs L402 documentation As of 2026-10-22
Who pays fees	The x402.org page says zero protocol fees, and that nominal payment network fees still apply. It says the flow is free for the customer and the merchant aside from those network fees. x402 site As of 2026-10-22 Not documented as of 2026-10-22. The same page does not say which party pays the nominal payment network fee. x402 site As of 2026-10-22	Stripe's MPP documentation says Stripe can cover the customer's Tempo network fees when hostedFeePayer is enabled. Stripe documentation for MPP As of 2026-10-22 Not documented as of 2026-10-22. The FAQ says pricing is set per service and describes near zero per request fees for sessions. It does not name one party that pays network fees on every rail. MPP FAQ As of 2026-10-22	Not documented as of 2026-10-22. Stripe's ACP page and the delegate payment reference do not say who pays fees. Stripe documentation for the Agentic Commerce Protocol As of 2026-10-22	Not documented as of 2026-10-22. The site and the payment mandate page do not say who pays card fees or network fees. AP2 protocol documentation As of 2026-10-22	Not documented as of 2026-10-22. The page says the client pays the Lightning invoice. It does not say who pays routing fees. Lightning Labs L402 documentation As of 2026-10-22
Spend controls and mandates	The Coinbase how it works page says a seller can charge a fixed price, authorize a maximum and settle only what was used, or defer settlement for a batch of payments. Coinbase documentation for how x402 works As of 2026-10-22 Not documented as of 2026-10-22. That page and x402.org do not define a buyer spend cap, a mandate, or a revoke call. Coinbase documentation for how x402 works As of 2026-10-22	The managing agent spend guide says Tempo access keys can set a token spending limit, a recipient restriction, an expiration, and a revocation path. Its example key can spend up to 10 OUSD per day and can transfer OUSD only to one recipient. Managing agent spend As of 2026-10-22	Per payment cap. max_amount is the maximum charge for that one time allowance. ACP delegate payment As of 2026-10-22 merchant_id names the one merchant that may use the token. ACP delegate payment As of 2026-10-22 Not documented as of 2026-10-22. Period budget. The allowance reason is one_time and the allowance has an expiry. A period budget is not stated. ACP delegate payment As of 2026-10-22 Not documented as of 2026-10-22. Human approval above a threshold. A risk signal can ask for manual review. A spend approval threshold is not stated. expires_at ends the allowance. The page does not state a revoke call. ACP delegate payment As of 2026-10-22	Amount range constrains the payment mandate amount. Budget is a total cap used with agent recurrence. Allowed payee limits the payee to a set of merchants. AP2 payment mandate As of 2026-10-22 Agent recurrence sets a frequency and an optional maximum number of occurrences so the mandate can be reused. AP2 payment mandate As of 2026-10-22 Not documented as of 2026-10-22. Revocation. The payment mandate page defines an expiration timestamp. It does not define a revoke call. AP2 payment mandate As of 2026-10-22	The page says the bearer can attenuate a macaroon before passing it on, for example to read access or to specific directories. Lightning Labs L402 documentation As of 2026-10-22 Not documented as of 2026-10-22. The page does not state a currency spend cap, a period budget, or a revoke call. Lightning Labs L402 documentation As of 2026-10-22
Identity and authorization	The Coinbase how it works page says the client signs a payment and sends the request again with proof of payment. Coinbase documentation for how x402 works As of 2026-10-22 The x402.org page says no accounts or personal information are needed. x402 site As of 2026-10-22 Not documented as of 2026-10-22. Those pages do not name a separate agent identity credential. x402 site As of 2026-10-22	The identity page says request attestation verifies which automated client sent a request, and an MPP Credential verifies the key that authorized payment. It says an attestation does not authorize a payment. Request attestation can use Web Bot Auth or the Trusted Agent Protocol. MPP identity As of 2026-10-22	Stripe's ACP page says delegated authentication uses OAuth 2.0 so an agent can act for a buyer with a business. Stripe documentation for the Agentic Commerce Protocol As of 2026-10-22 The delegate payment reference says API requests use a bearer token issued by the merchant. ACP delegate payment As of 2026-10-22	The site says checkout and payment mandates are signed verifiable digital credentials. The payment mandate page says the shopping agent creates the content and a trusted surface renders it to the user. AP2 protocol documentation As of 2026-10-22	The client presents the token with the preimage. The recommended token format is a macaroon. The server can check payment without a lookup. Lightning Labs L402 documentation As of 2026-10-22
Open spec and license	Apache-2.0. The GitHub license API reported this SPDX identifier on 2026-10-22. The x402.org page calls the protocol an open standard. GitHub repository x402-foundation/x402 As of 2026-10-22	Apache-2.0 for the tempoxyz/mpp repository. The GitHub license API reported this SPDX identifier on 2026-10-22. GitHub repository tempoxyz/mpp As of 2026-10-22 The governance page says the IETF submission is under IETF Trust licensing, BCP 78 and BCP 79, and that code components in that document use the Revised BSD License. MPP governance As of 2026-10-22	Apache-2.0. The repository README states the Apache 2.0 License. The GitHub license API reported Apache-2.0 on 2026-10-22. Agentic Commerce Protocol repository As of 2026-10-22	Apache-2.0. The GitHub license API reported this SPDX identifier on 2026-10-22. GitHub repository google-agentic-commerce/AP2 As of 2026-10-22	MIT for the Aperture repository, which the L402 page calls an implementation. The GitHub license API reported this SPDX identifier on 2026-10-22. GitHub repository lightninglabs/aperture As of 2026-10-22 Not documented as of 2026-10-22. The L402 documentation page does not state a license for the protocol text. The page itself is public. Lightning Labs L402 documentation As of 2026-10-22
Status	Live. The x402.org FAQ says the protocol is production ready. x402 site As of 2026-10-22 The Linux Foundation announced the operational launch of the x402 Foundation on 14 July 2026. Linux Foundation announcement of the x402 Foundation, 14 July 2026 As of 2026-10-22	Live. The FAQ says Tempo stablecoin payments, card payments, and Lightning payments are in production. MPP FAQ As of 2026-10-22 Not documented as of 2026-10-22. The FAQ and the governance page do not state a launch date. MPP governance As of 2026-10-22	Beta. The repository README says the specification is currently in beta. The spec directory lists an initial release dated 2025-09-29. Agentic Commerce Protocol repository As of 2026-10-22	The site lists an announcement dated 9/16/2025. It says the public repository hosts the current specification while FIDO continues the standards work. AP2 protocol documentation As of 2026-10-22 The v0.2.0 release, published on 2026-04-28, says it focuses on human not present flows. AP2 v0.2.0 release on GitHub As of 2026-10-22	The documentation presents L402 as the current standard for this HTTP 402 flow. Lightning Labs L402 documentation As of 2026-10-22 Not documented as of 2026-10-22. The page does not state a launch date. Lightning Labs L402 documentation As of 2026-10-22
Listed products	Coinbase Agentic Wallet. The welcome page says agents use the awal CLI to pay for x402 services, and that the MCP version can pay x402. Listing Coinbase Agentic Wallet documentation overview As of 2026-10-22 Concordium Agent Registry. The 20 October 2026 post says x402 payments now settle on Concordium. Listing Concordium Agent Registry update, 2026-10-20 As of 2026-10-22 Mastercard Agent Pay for Machines. The 20 October 2026 article says Agent Pay for Machines builds on x402. Listing Mastercard Agent Pay for Machines at Cloudflare Connect, 2026-10-20 As of 2026-10-21 MetaMask Agent Wallet. The guide says the wallet pays for HTTP resources that return 402 using the x402 protocol. Listing MetaMask Agent Wallet guide to pay for APIs with x402 As of 2026-10-22 Nevermined. The facilitator page says Nevermined verifies and settles both x402 and MPP payments against the same payment plans. Listing Nevermined payments facilitator As of 2026-10-22 Polygon Agent CLI. The CLI reference includes an x402 pay command and a max usd flag. Listing Polygon Agent CLI reference As of 2026-10-22	Nevermined. The facilitator page says Nevermined verifies and settles both x402 and MPP payments against the same payment plans. Listing Nevermined payments facilitator As of 2026-10-22 Stripe link-cli. The README says a Shared Payment Token is for sellers that accept programmatic payments through MPP. Listing stripe/link-cli README As of 2026-10-22 Tempo Wallet. The pay with the CLI page says the CLI handles the MPP challenge and payment retry, and that a max spend flag caps spending for the command. Listing Tempo guide to paying with the CLI As of 2026-10-22	Not documented as of 2026-10-22. The Stripe ACP page and the repository README do not name another listing in this directory. Stripe documentation for the Agentic Commerce Protocol As of 2026-10-22	Not documented as of 2026-10-22. The AP2 site links its own samples, including a human not present sample that uses x402. It does not name another listing in this directory as an implementer. AP2 protocol documentation As of 2026-10-22	Not documented as of 2026-10-22. The L402 page names Aperture as an implementation and does not name another listing in this directory. Lightning Labs L402 documentation As of 2026-10-22

How this works

The default columns are x402, Machine Payments Protocol, and Agentic Commerce Protocol, in that order. AP2 and L402 are extra columns. The links are ordinary URLs, so the table is readable without JavaScript. The JSON file always includes all five columns.

A filled cell quotes a primary page and the day that page was read. Not documented means that page does not state the fact. It is not a claim that the fact is false.

The use selector marks columns. It does not hide the others, and it does not rank them.

Listed products are other directory listings whose own primary page says they use the protocol. This page does not quote x402 volume. How x402 volume is measured compares the public figures.

Pairwise comparisons

Questions

What does Not documented mean?: Not documented means the page checked for that cell does not state the fact. The cell still links that page and the day it was read. It is not a claim that the fact is false.
Does the use selector pick a protocol?: No. It marks the columns whose cited pages describe that job. The other visible columns stay in the table. The mark is not a ranking.
Where are AP2 and L402?: Both are listings in this directory, so the page can show them as extra columns. The default HTML shows x402, MPP, and ACP. The JSON file includes all five.
Where is the machine readable comparison?: GET /data/agent-payment-protocols.json. The file includes every column, the cited sources, and the as of dates. The HTML table shows the columns named in the page URL.
Why is there no x402 volume on this page?: This page does not quote an x402 volume. The measurement page lists each public figure with its source and the day it was read.

Sources

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