Platform events are provided by platform
[integrations](https://docs.cloud.google.com/dialogflow/docs/integrations).
They are invoked when platform-specific events occur.
See the documentation for your integration platform
for details on platform-specific events.

## Welcome events

Welcome events are invoked when a conversation is started.
There are two types of welcome events:

- **Generic welcome event** : The [default welcome intent](https://docs.cloud.google.com/dialogflow/docs/intents-default#welcome) is automatically created when you create an agent. This intent is preconfigured to handle the generic welcome event: `WELCOME`.
- **Platform-specific welcome events** : Each platform invokes a platform-specific welcome event when a conversation starts. For example, if an end-user clicks the **Get started** button to start a chat with your Facebook Messenger bot, the [`FACEBOOK_WELCOME` event](https://docs.cloud.google.com/dialogflow/docs/integrations/facebook#events) is invoked.

When a platform-specific welcome event is invoked,
Dialogflow triggers any intent that is configured for the event.
If no intent is configured for the platform-specific welcome event,
Dialogflow invokes the generic welcome event,
which triggers the default welcome intent.

## Google Assistant events

Dialogflow events are referred to as "intents" in Google Assistant documentation.
For more information and a list of events, see the
[reference documentation for Google Assistant intents](https://developers.google.com/assistant/conversational/reference/rest/intents).