> ## Documentation Index
> Fetch the complete documentation index at: https://developer.hellgate.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Eventing Reference

> Reference for Cloud Events exchanged between Commerce V1 and your integration services.

Commerce V1 uses the [CloudEvents 1.0 specification](https://cloudevents.io/) for asynchronous service-to-service communication. Events flow between Commerce and your [extension services](/products/commerce/v1/integration/extensions/overview) and [processor integrations](/products/commerce/v1/integration/processors/processor-integration) via the mTLS-secured event bridge.

<Frame>
  <img src="https://mintcdn.com/starfishgmbhcokg/dfhj2Hm84A9ik5S0/images/commerce/v1/cloud-event-bridge.png?fit=max&auto=format&n=dfhj2Hm84A9ik5S0&q=85&s=40bb80527d74b11737b5dec2b15d53e4" alt="Diagram showing the Cloud Event Bridge architecture in Commerce V1" width="3649" height="1683" data-path="images/commerce/v1/cloud-event-bridge.png" />
</Frame>

## Event Envelope

All events follow the [CloudEvents HTTP binding](https://github.com/cloudevents/spec/blob/main/cloudevents/bindings/http-protocol-binding.md) with these required attributes:

| Attribute        | Description                                       |
| ---------------- | ------------------------------------------------- |
| `ce-specversion` | Always `1.0`                                      |
| `ce-type`        | Identifies the event (e.g., `CardSessionCreated`) |
| `ce-source`      | Event source URI                                  |
| `ce-id`          | Unique event identifier (UUID)                    |
| `ce-time`        | RFC 3339 timestamp                                |
| `Content-Type`   | `application/json`                                |

## Inbound Events

Events sent to Commerce by your integration services.

| Event                                                                                         | Description                                    |
| --------------------------------------------------------------------------------------------- | ---------------------------------------------- |
| [`CardSessionCreated`](/products/commerce/v1/eventing-reference/inbound/card-session-created) | Successful card session result                 |
| [`CardSessionFailed`](/products/commerce/v1/eventing-reference/inbound/card-session-failed)   | Card session could not be completed            |
| [`TDSResult`](/products/commerce/v1/eventing-reference/inbound/tds-result)                    | Outcome of a 3-D Secure challenge              |
| [`Finish`](/products/commerce/v1/eventing-reference/inbound/finish)                           | Transaction result from an integration service |

## Outbound Events

Events sent by Commerce to your integration services.

| Event                                                                                                         | Description                         |
| ------------------------------------------------------------------------------------------------------------- | ----------------------------------- |
| [`CompleteTDSSession`](/products/commerce/v1/eventing-reference/outbound/complete-tds-session)                | Outcome of a 3-D Secure session     |
| [`SessionVoided`](/products/commerce/v1/eventing-reference/outbound/session-voided)                           | A payment session was voided        |
| [`StateChanged`](/products/commerce/v1/eventing-reference/outbound/state-changed)                             | Payment state changed               |
| [Custom Transaction Event](/products/commerce/v1/eventing-reference/outbound/custom-transaction-event)        | Flow reached a transaction node     |
| [`UbersichtEvent`](/products/commerce/v1/eventing-reference/outbound/ubersicht-event)                         | Payment lifecycle notification      |
| [`CustomerCreated`](/products/commerce/v1/eventing-reference/outbound/customer-created)                       | A new customer was created          |
| [`PaymentMethodSetupChanged`](/products/commerce/v1/eventing-reference/outbound/payment-method-setup-changed) | Payment method setup status changed |
| [`SettlementEvent`](/products/commerce/v1/eventing-reference/outbound/settlement-event)                       | Settlement activity on a payment    |