Skip to main content
Version: CORE v. go-2.1

Payto Protocol

Specification: PAYTO Uniform Resource Identifier (URI) Scheme​

This memo introduces an interim URI scheme for resources that identify a payment recipient. Typically, these resources are resolved by making a payment to the designated recipient. However, resolution can also encompass non-financial operations, such as sending a message to the recipient. This interpretation expands on RFC 8905.

PAYTO URI Scheme​

Introduction​

The PAYTO URI scheme designates the recipient of a payment. The resource designated by this URI is the recipient itself. Typically, when a PAYTO URI is "dereferenced" (used within a context that expects a URI to provide a representation of the resource it identifies), a payment is made to the designated recipient.

Scheme Syntax​

This document defines the 'payto' Uniform Resource Identifier (URI) scheme to designate transfer form data for payments.

The general syntax is:

payto-URI = "payto://" authority path-abempty [ "?" opts ]
    opts = opt *( "&" opt )
    opt-name = generic-opt / authority-specific-opt
    opt-value = *pchar
    opt = opt-name "=" opt-value
    generic-opt = "amount" / "receiver-name" / "sender-name" /
                  "message" / "instruction"
    authority-specific-opt = ALPHA *( ALPHA / DIGIT / "-" / "." )
    authority = ALPHA *( ALPHA / DIGIT / "-" / "." )

Operations​

The primary operation on a PAYTO URI is its resolution. This is typically accomplished by making a payment to the designated recipient.

Scheme​

ICAN​

In the ICAN (International Crypto Asset Network), the 'payto' scheme is employed. Typically, the address is a cryptocurrency wallet address, and the amount indicates the number of crypto coins to be sent, separated by ':'. The network field specifies the blockchain for the transaction.

Example:

payto://xcb/cb00…?amount=CTN:3.14

This example signals a request to pay 3.14 CTN tokens to the address cb00… on the XCB (Core Blockchain) network.

Additional parameters for ICAN:

  • Instead of amount, you can use fiat to indicate the use of Fiat (government-issued money) as the value.

Example:

payto://xcb/cb00…?fiat=USD:50
  • Implement the dl parameter to set an expiration time for the transaction, expressed in the local timezone and converted to a UNIX timestamp in seconds.

Example:

payto://xcb/cb00…?amount=CTN:3.14&dl=1677312123
  • Include the rc parameter to set up recurring payments. The accepted values are y for yearly, m for monthly, d for daily. If d is prefixed with a number between 2-365, it indicates the recurrence every "number" of days. Due to varying month lengths, if a chosen day doesn't exist in a subsequent month, the payment will execute on the last day of that month.

Example:

payto://xcb/cb00…?amount=CTN:3.14&rc=d15

CorePass current support​

CorePass currently supports the following assets:

  • CTN (Core Token)
  • XCB (Core Blockchain)

And the following actions:

  • Initiate a payment by link
  • Initiate a payment by QR code
  • Prefill a payment form

Security Considerations​

Always validate the authenticity and correctness of PAYTO URIs. Due to the irreversible nature of crypto asset transactions, users should confirm both the recipient's address and the amount before initiating a transfer.

Normative References​

RFC3986: (Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier URI: Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005.)

RFC8905: (Thaler, D.), "The 'payto' URI Scheme for Payments", RFC