Initiation API

  • Updated on Sep 15, 2025
  • Published on Jul 9, 2025
  • 1 minute(s) read
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Initiating an account to account payment via the ISO20022 API

What is the ISO20022 API

ISO20022 is the global standard for financial messaging that enables structured, rich and interoperable communication across financial institutions. In an A2A payment flow, a payer´s bank or payment processor sends a payment initiation request to the payee´s bank or payment processor. Using the ISO20022 standard ensures that all parties exchange consistent machine readable data to support real-time processsing reconciliation and compliance requirements.

 

What do I need to use the initiation API?

In order to use the initiation API you will have to go through an onboarding process where different configurations will be decided and you will be given access to the relevant environment (Sandbox, Pre and Live / Production).

 

How can I access Pre and Live environments?

Application forms are submitted via the developer portal client log in area and must be completed with the following information:

Product and environment details:

  • APIs: Which PagoNxt Payments product do you want to use?

  • Environment: In which environment do you need access?

Technical information:

  • KID: The KID (key id) is the identifier of the key used to sign the token, we use this value to check the signature.

  • Issuer: The Issuer (iss field of a JWT) identifies the entity that issued the token. This can be a person, company, service, etc.

  • Public key and private key: A pair of keys related within them. Only the public key is shared with PagoNxt Payments Hub because the private one is kept secret and is used in the JWT token you generate to authenticate into our OAuth Server.

Public and private keys can be generated using the following command lines in order:

  • Private key: ssh-keygen -t rsa -m PEM -f kidName.key.

  • Public key: openssl rsa -in kidName.key -pubout -outform PEM -out kidName.key.pub

The result of these command lines are two text files with the key pairs.
Webhooks URLs: URLs where the PH will notify all the messages and their updated status (optional).

Notifications endpoint subscription:

  • Status report hub message: It can either be a pacs.002 or camt.029 with the details of the payment’s status.

  • Webhook: Contains the URIs that can be used to retrieve the payment or status report.

  • OAuth2.0: Industry standard protocol for authorization.

  • HTTP Basic: User and password-based authentication.

 

Where can I find examples of payloads according to scheme or type of message?

You can find tutorials on all of our messages plus examples per scheme in the Payment Message Tutorials section