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External Host Interface Integration Guide

4. How the Integration Works

Payblr forwards EHI transaction messages to your configured endpoint using the EHI model discussed earlier.

When Payblr receives an EHI message from the transaction flow, Payblr routes the message to your endpoint, signs the outbound request, and forwards the original EHI payload to your system. Your system validates the Payblr request, process the EHI message, and returns the required EHI response.

Payblr then relays your response through the transaction flow.

On this page

EHI Sequence Diagram

Recommended EHI request and response sequence

Platform

Payblr

System

Your Systems

1. Forward original EHI payload

Request / Response

Payblr forwards the original EHI authorization, reversal, or advice message to your configured endpoint.

PayblrYour Systems

2. Validate Payblr request headers

Request / Response

Your systems validate the required Payblr request headers before processing the EHI message.

Your SystemsprocessesYour Systems

3. Process original EHI message

Your systems read and process the original EHI message fields without requiring Payblr to transform the payload.

Your SystemsprocessesYour Systems

4. Apply authorization, matching, balance, or reconciliation logic

Your systems apply the required business logic based on the EHI message type and transaction context.

Your SystemsprocessesYour Systems

5. Return required EHI response

Request / Response

Your systems return the required EHI response to Payblr within the expected timeout window.

Your SystemsPayblr

6. Relay response through transaction flow

Payblr relays the response through the transaction flow.

PayblrprocessesPayblr
sequenceLaneCenter(index, columnCount)
Styled sequence diagram for the EHI request and response flow.

4.1 General flow

The general flow for EHI messages is as follows:

  1. 1. Payblr receives an EHI transaction message – Payblr receives the transaction message from the EHI transaction flow.
  2. 2. Payblr signs and forwards the outbound request – Payblr signs the request before forwarding it so your system can validate that the message came from Payblr. Payblr then sends the EHI payload to your system.
  3. 3. Your system validates the request – Your system validates Payblr’s signature and request timestamp before processing the transaction message.
  4. 4. Your system processes the EHI message – Your system processes the EHI message using the fields provided in the payload.
  5. 5. Your system returns the required EHI response – Your system returns the applicable response based on the message type, such as an authorization decision or acknowledgement.
  6. 6. Payblr relays your response – Payblr relays the response returned by your system through the transaction flow.
1

Payblr receives an EHI transaction message

Payblr receives the transaction message from the EHI transaction flow.

2

Payblr signs and forwards the outbound request

Payblr signs the request before forwarding it so your system can validate that the message came from Payblr. Payblr then sends the EHI payload to your system.

3

Your system validates the request

Your system validates Payblr’s signature and request timestamp before processing the transaction message.

4

Your system processes the EHI message

Your system processes the EHI message using the fields provided in the payload.

5

Your system returns the required EHI response

Your system returns the applicable response based on the message type, such as an authorization decision or acknowledgement.

6

Payblr relays your response

Payblr relays the response returned by your system through the transaction flow.

Next steps

Continue to Security Requirements.