UCP payment handlers declared

What we check

We read ucp.payment_handlers, the registry of how your checkout takes payment, keyed by reverse-domain name, such as com.google.pay or dev.shopify.shop_pay. For each entry we report its namespace, id and version, and for Google Pay the gateway it names.

Why it matters

The UCP overview makes payment_handlers required for every business profile, and the registry must be present even when it is empty. An empty registry gives an agent no way to pay that it can see. Entries without an id or a version leave the agent unable to tell which handler or which release you mean.

How we check

This check uses the profile the scan already read, so it makes no extra request. PASS: at least one handler, each with an id and a version. WARN (score 30): the registry is present but empty. If some entries lack an id or a version, the score is the share that have both: 80 or more is a PASS, 40 or more is a WARN and below 40 is a FAIL. FAIL: payment_handlers is missing, or the profile has no ucp.version and so declares nothing. SKIPPED: there is no profile, we could not read it, or it is not JSON.

How to fix it

1. Declare the payment handlers your checkout accepts under ucp.payment_handlers. Your platform or payment provider documents its handler namespace.
2. Give every handler entry its id and version.

What good looks like

"payment_handlers": {
  "com.google.pay": [{ "id": "gpay", "version": "2026-01-11", ... }],
  "dev.shopify.shop_pay": [{ "id": "shop_pay", "version": "2026-04-08", ... }]
}

Sources

• UCP 2026-08-25 specification: overview
• UCP 2026-08-25 base schema (ucp.json)
• UCP Checker: how we check

Read more

• UCP explained

  The Universal Commerce Protocol: the profile a store publishes at /.well-known/ucp, the capabilities it declares there, and the checkout flow from a new basket to a placed order.

• How an agent pays without seeing your card

  Tokenised and delegated payment: Stripe Shared Payment Tokens, ACP’s delegated payment, what Adyen’s and PayPal’s documents describe, Visa’s Trusted Agent Protocol and AP2’s mandates.