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

# Events

> Flow-level events, and the state of the platform event surface.

<Note>
  Core does not publish a catalogue of platform events yet. There is no stable
  set of domain events an extension can subscribe to, and this page will not
  invent one. What exists today is the flow-level event mechanism described
  below.
</Note>

## Flow events

A flow emits an event through the `emit_event` node. Emission is queued rather
than synchronous — `QueuedFlowTriggerEventPublisher` hands it to the
`scheduled.triggers` queue, so a flow that emits does not wait for whatever
consumes the event.

## Triggers

What an event causes is resolved through the trigger contracts in
`fapost/foundation`:

| Contract                                      | Role                                           |
| --------------------------------------------- | ---------------------------------------------- |
| `Flow\Contracts\TriggerResolverInterface`     | Resolves which flow an incoming trigger starts |
| `Flow\Contracts\TriggerTypeResolverInterface` | Resolves the kind of a trigger                 |
| `Flow\DTO\ResolvedTrigger`                    | The resolution result                          |
| `Flow\DTO\TriggerContext`                     | The context a trigger carries                  |

Trigger fan-out runs on `scheduled.triggers`, separate from message handling, so a
broad fan-out cannot delay a conversation — see [Queues](/reference/queues).

## Analytics

Analytics is a distinct stream, not the event bus. It is written through
`Analytics\Contracts\AnalyticsWriterInterface` with `AnalyticsEvent` and
`AnalyticsEventType`, and it exists to record what happened rather than to
trigger behaviour.

## History

`Flow\History\HistoryEventType` enumerates the event kinds recorded against a
flow session's history. It is a record of session progression, readable after the
fact — not a subscription surface.

## If you need to react to something

Today that means a node handler on the flow, or a registered schedule — see
[Building a Plugin](/extending/plugins). If the reaction you need cannot be
expressed either way, that is a missing contract in `fapost/foundation`, and the
right move is to propose it rather than to hook into a Core internal that carries
no stability promise.