# Event Notification Subscription API Profile - v4.0.1

Overview
Basics
- Overview
  - Steps
  - Sequence Diagram
- Subscriptions for Real Time Event Notifications and Aggregated Polling
  - Real Time Event Notifications
  - Aggregated Polling

# Overview

The Event Notification Subscription API Profile describes the flows and common functionality for the Event Notification Subscription API, which allows a TPPs to:

Register an event subscription with an ASPSP to subscribe to event notifications.
- A subscription can enable real time event notifications via a HTTP callback from the ASPSP, and aggregated polling by the TPP.
Specify a list of event types to be notified on.
Optionally read, update or delete a registered event subscription.

This profile should be read in conjunction with a compatible Read/Write Data API Profile, a compatible Event Notification API Profile and compatible individual resources.

# Basics

# Overview

The steps and sequence diagram below provide a general outline of a notification flow for all resources in the R/W APIs.

# Steps

Step 1: Setup Event Notification Subscription

This flow begins with a TPP creating an event-subscription resource with an ASPSP.

Step 2: Retrieve/Update/Delete Event Notification Subscription

The TPP may optionally read/update/delete the event-subscription resource.

# Sequence Diagram

Event Subscriptions

Diagram source

participant TPP
participant ASPSP Authorisation Server
participant ASPSP Resource Server
participant ASPSP Notification Service

note over TPP, ASPSP Notification Service
Step 1: Setup Event Subscription
end note

TPP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
TPP -> ASPSP Authorisation Server: Initiate Client Credentials Grant
ASPSP Authorisation Server -> TPP: access-token
TPP <-> ASPSP Resource Server: Establish TLS 1.2 MA
TPP -> ASPSP Resource Server: POST /event-subscriptions
ASPSP Resource Server -> TPP: HTTP 201 (Created),  EventSubscriptionId

note over TPP, ASPSP Notification Service
Step 2: Retrieve/Update/Delete Event Subscription
end note

TPP <-> ASPSP Authorisation Server: Establish TLS 1.2 MA
TPP -> ASPSP Authorisation Server: Initiate Client Credentials Grant
ASPSP Authorisation Server -> TPP: access-token
TPP <-> ASPSP Resource Server: Establish TLS 1.2 MA
alt Retrive
TPP -> ASPSP Resource Server: GET /event-subscriptions
ASPSP Resource Server -> TPP: HTTP 200 (OK)
else Update
TPP -> ASPSP Resource Server: PUT /event-subscriptions/{EventSubscriptionId}
ASPSP Resource Server -> TPP: HTTP 200 (OK)
else Delete
TPP -> ASPSP Resource Server: DELETE /event-subscriptions/{EventSubscriptionId}
ASPSP Resource Server -> TPP: HTTP 204 (OK)
end alt
option footer=bar

# Subscriptions for Real Time Event Notifications and Aggregated Polling

ASPSPs may choose to offer Real Time Notifications, Aggregated Polling or a combination of both. TPPs will subscribe to the different notification mechanisms using the event-subscription resource.

# Real Time Event Notifications

TPPs must register an event subscription with a CallbackUrl for TPP hosted services to receive real time event notifications from an ASPSP (providing an ASPSP supports this functionality).

The CallbackUrl must end with the Event Notification API specification version number, followed by ‘/event-notifications'.

For example:

URL: https://tpp.com/open-banking/v4.0/event-notifications

# Aggregated Polling

TPPs must register an event subscription to enable aggregated polling on an ASPSP (providing an ASPSP supports this functionality).

← Usage Examples Callback URL API→