1.1 Validity

The steps to validate a payment method identifier with a string pmi are given by the following algorithm. It returns true if the pmi is valid.

1. Let url be the result of running the basic URL parser with pmi.
2. If url is failure, validate a standardized payment method identifier with pmi and return the result.
3. Otherwise, validate a URL-based payment method identifier passing url and return the result.

2.1 Validation

The steps to validate a URL-based payment method identifier are given by the following algorithm. The algorithm takes a URL url as input and returns true if the URL is valid:

1. If url's scheme is not "https", return false.
2. If url's username or password is not the empty string, return false.
3. Otherwise, return true.

const valid = [
  {
    supportedMethods: "https://example.com/pay",
  },
  {
    supportedMethods: "https://example.com/pay?version=1",
  },
  {
    supportedMethods: "https://example.com/pay/version/1",
  },
];

const invalid = [
  {
    // ❌ Uses http://, a username, and a password.
    supportedMethods: "http://username:password@example.com/pay",
  },
  {
    // ❌ Uses unknown URI scheme.
    supportedMethods: "unknown://example.com/pay",
  },
];

2.2 Comparison

User agents MUST perform comparisons of URL-based payment method identifiers using equals. [URL]

2.3 Fetching (dereferencing)

It is OPTIONAL for user agents to fetch a URL-based payment method identifier.

3.1 Validity

The steps to validate a standardized payment method identifier are given by the following algorithm. The algorithm takes a string as input and returns true if the identifier is valid:

1. Return true if string contains only [UNICODE] code points:
   1. In the range U+0061-U+007A ("Latin Small Letter A" to "Latin Small Letter Z")
   2. In the range U+0030-U+0039 ("Digit Zero" to "Digit Nine").
   3. Zero or more U+002D HYPHEN-MINUS (-).
2. Otherwise, return false.

const valid = [
  {
    supportedMethods: "basic-card",
  },
];

const invalid = [
  {
    // ❌ Contains Unicode character outside the valid ranges.
    supportedMethods: "basic-💳",
  },
  {
    // ❌ Contains uppercase characters.
    supportedMethods: "Basic-Card",
  },
  {
    // ❌ Contains Unicode characters outside the valid ranges.
    supportedMethods: "¡basic-*-card!",
  },
];

3.2 Comparison

For standardized payment method identifiers, user agents MUST compare strings in a case-sensitive manner (code point for code point).