Event types

Every event outbound webhooks can send, the envelope each one arrives in, the fields in its data and the JSON Schema that describes it, with a full example.

Each event type names something that happened in your workspace. You choose the types an endpoint receives when you set it up, and you can change them later.

Each event also has a reference page with every field, the signature headers and an example request: app.created.v1, app.published.v1, app.unpublished.v1, app.deleted.v1, app.restored.v1, chat.turn_started.v1, chat.turn_ended.v1 and webhook.test.v1.

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The envelope

Every request body is a CloudEvents 1.0 JSON document, sent with Content-Type: application/json. The same attributes appear on every event, and data holds the fields for that event type.

Attribute	Value
specversion	Always 1.0.
id	The event’s unique ID, such as evt_68c1d2e3f4a5b6c7d8e9f0a1. It’s the same on every retry, so use it to ignore duplicates.
source	Your workspace, as https://base44.com/workspaces/{workspace_id}.
type	The event type, such as app.created.v1.
subject	What the event is about, as apps/{app_id}.
time	When the change happened, in UTC.
datacontenttype	Always application/json.
dataschema	The URL of the JSON Schema for data.
traceparent, tracestate	W3C trace context, only when present.
authtype	Who made the change: user, api_key (a workspace API key) or system (no person or key, for example a background job). Treat any other value as unknown.
authid	The ID of the user or API key that made the change. An empty string when authtype is system.
data	The event’s own fields, listed below.

Every timestamp, in time and in data, uses one format: 2026-09-01T10:15:30.123Z.

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App events

These 5 events let you keep a copy of each app’s state in your own system. Every one carries the same 3 identifying fields, plus a timestamp for the change.

Field	Description
app_id	The app the event is about.
workspace_id	The workspace the app belongs to.
owner_id	The Base44 ID of the app’s current owner.

Events carry IDs only. App names, app content and personal details are never included.

Event type	Sent when	Extra fields
app.created.v1	An app is created, including by cloning or importing.	app_type, created_at
app.published.v1	A version of an app goes live.	published_version, published_at
app.unpublished.v1	An app is taken offline, by a person or automatically (for example by a workspace policy or a plan change).	unpublished_at
app.deleted.v1	An app is moved to trash.	deleted_at
app.restored.v1	An app is restored from trash.	restored_at

app_type is one of user_app (an app), user_agent (a Superagent), user_game (a game) or imported_app (an app imported from a repository). Treat published_version as an opaque string.

app.deleted.v1 means the app moved to trash, not that it’s gone. It can still be restored, and app.restored.v1 tells you when it is. Don’t delete your own copy of the app’s data when you receive it.

Example: app.created.v1

A complete request body for a new app:

{
  "specversion": "1.0",
  "id": "evt_68c1d2e3f4a5b6c7d8e9f0a1",
  "source": "https://base44.com/workspaces/68a1b2c3d4e5f6a7b8c9d0e1",
  "type": "app.created.v1",
  "subject": "apps/68b0c1d2e3f4a5b6c7d8e9f0",
  "time": "2026-09-01T10:15:30.123Z",
  "datacontenttype": "application/json",
  "dataschema": "https://base44.com/webhooks/schemas/app.created.v1.json",
  "authtype": "user",
  "authid": "6899aabbccddeeff00112233",
  "data": {
    "app_id": "68b0c1d2e3f4a5b6c7d8e9f0",
    "workspace_id": "68a1b2c3d4e5f6a7b8c9d0e1",
    "owner_id": "6899aabbccddeeff00112233",
    "app_type": "user_app",
    "created_at": "2026-09-01T10:15:30.123Z"
  }
}

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AI chat events

These 2 events tell you when the AI works on a message sent to an app’s AI chat, so a platform that sends messages from its own server doesn’t have to hold the request open or poll for the result. A turn is one message and everything the AI does in response.

Both carry the 3 identifying fields of the app events, plus:

Field	Description
message_id	The message that started the turn: the ID returned when you sent it. Both events of a turn carry the same one.
conversation_id	The conversation the message belongs to. Left out when there isn’t one.
started_at	When the AI started working on the message.
continues_message_id	Set when this turn continues one that was interrupted: the message_id of that turn. Follow it back to add up how long the whole response took. Left out otherwise.

Event type	Sent when	Extra fields
chat.turn_started.v1	The AI picks the message up. A message sent while another turn runs waits until then.
chat.turn_ended.v1	The turn ends. Each turn ends once.	status, ended_at

status is one of:

• finished: the AI replied and has nothing pending.
• waiting_for_user_input: the AI stopped to ask something, such as a clarifying question or a plan to approve. It continues when the next message answers it.
• failed: the turn hit an error.
• cancelled: the turn was stopped before it ended.
• interrupted: the AI was interrupted, for example by a restart. It continues in a new turn whose continues_message_id is this turn’s message_id.

These events used to be called builder.turn_started.v1 and builder.turn_ended.v1, with the same fields. Base44 now sends them only as chat.turn_started.v1 and chat.turn_ended.v1, so an endpoint that still selects the old names receives nothing. To keep getting them, select the new names in Settings, where the old ones show as retired. With the API, call PATCH /api/v1/outbound-webhooks/endpoints/{endpoint_id} and pass the endpoint’s full selected_event_types list, with the new names in place of the old ones. A list that still includes an old name is rejected. Then update any receiver code that checks type or dataschema.

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The activation test

Base44 sends webhook.test.v1 when an endpoint is activated or tested. You can’t select it, and it’s sent to every endpoint that’s being activated. Its subject is endpoints/{endpoint_id}.

Field	Description
endpoint_id	The endpoint being activated.
workspace_id	The workspace the endpoint belongs to.
sent_at	When the test was sent.
challenge	Return this value in your response body to activate the endpoint.

To learn how to answer it, see Echoing the challenge.

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JSON Schemas

Each event type has a JSON Schema for its data, at the URL in the event’s dataschema attribute:

Event type	Schema
app.created.v1	app.created.v1.json
app.published.v1	app.published.v1.json
app.unpublished.v1	app.unpublished.v1.json
app.deleted.v1	app.deleted.v1.json
app.restored.v1	app.restored.v1.json
chat.turn_started.v1	chat.turn_started.v1.json
chat.turn_ended.v1	chat.turn_ended.v1.json
webhook.test.v1	webhook.test.v1.json

When an event’s fields change in a way that could break your receiver, Base44 adds a new version, such as app.created.v2, and keeps sending the old version to endpoints that selected it for a support period.

The Audit Logs API has events with similar names, such as app.created. They’re a separate record with their own fields, so the 2 can differ.