The expectation of the Web Payments Working Group is that those who mint payment method identifiers that are URLs (see [[METHOD-IDENTIFIERS]]) will also publish machine readable information that describes how that method participates in the PaymentRequest ecosystem. This specification defines the format and addressing of payment method manifest files.

Use Cases

This specification intends to address the following use cases:

  1. The owner of a payment method wishes to authorize only certain parties to distribute payment apps that are capable of implementing the payment method. In this use case, the browser helps to ensure that for that payment method, the user can only invoke payment apps from parties authorized by the owner of the payment method.
  2. In addition, the owner of a payment method wishes to confirm the authenticity of a particular payment app (e.g., via a digital signature for that app).
  3. When the user has not yet installed a payment app for a payment method, the user agent can provided an improved user experience for procuring a payment app.

Manifest File Format

Define here the overall file format in a way that enables forward and backward compatibility.

Extensibility

The expectation is that the manifest contents may change over time. What is our extensibility mechanism?

Error Handling

How are unrecognized names handled? Bad values?

Payment App Data

This specification defines two sections of a payment method manifest file:

In the following example, the payment method owner has declared that:

      
	// payment-manifest.json
{
  // Android:
  "android": [{
    "package": "xyz.bobay.app",
    "version": "10",
    "sha256_cert_fingerprints": ["14:6D:E9:83:C5:73:06:50"],
    "platforms": {
      "play": "https://play.google.com/store/apps/details?id=com.bobspayments.app1"
    }
  }],
  // Web:
  "name": "Bob's Payments",
  "icons": [{
    "src": "icon/lowres.webp",
    "sizes": "48x48",                                                                                                                                                                                       
    "type": "image/webp"
  }, {
    "src": "icon/lowres",
    "sizes": "48x48"
  }, {
    "src": "icon/hd_hi.ico",
    "sizes": "72x72 96x96 128x128 256x256"
  }, {
    "src": "icon/hd_hi.svg",
    "sizes": "257x257"
  }],
  // iOS:
  "ios": {...},
  // Other supported payment apps:
  "externally_supported_apps": ["https://alicepay.com/pay"]
}

      

Origins Authorized to Distribute Payment Apps

Talk here in more detail about externally_supported_apps, etc.

Data about Authorized Payment Apps

Talk here in more detail about payment_apps, etc.

How is a default app identified?

Manifest File Addressing

See issue 19 about payment method manifest file addressing.

The following algorithm is used to determine the address of a payment manifest file given a payment method identifier PMI:

  1. This is in development. It may involve a sequence of checks, or a single mechanism. It may involve some or none of: deterministic construction of a new URL for the JSON, the use of HTTP headers, and the use of Content Negotiation.

Design Notes

  • For performance reasons, it is desirable to be able to retrieve all information about a payment method (both human-readable and machine-readable) in a single HTTP request. The Web Payments Working Group intends to look more closely about features of HTTP/2 to achieve this goal.
  • See the URL construction approach taken by Android's Digital Asset Links
  • Using an HTML link element may be too costly an approach as it would require fetching and parsing files.

Security Considerations

What happens when there is no payment method manifest available? Is it the responsibility of this specification to define a single error handling behavior? Or at least some security considerations?