Event types

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unpublished.v1, app.deleted.v1, app.restored.v1, builder.turn_started.v1, builder.turn_ended.v1 and webhook.test.v1.

The envelope

Every request body is a CloudEvents 1.0 JSON document. 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`.
`authtype`	Who made the change: `user`, `service_account`, `api_key` or `system`.
`authid`	The ID of whoever made the change, when there is one.
`data`	The event’s own fields, listed below.

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

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unpublished.v1`	An app is taken offline.	`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).

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"
  }
}

Builder events

These 2 events tell you when the AI builder works on a message sent to an app, 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 builder does in response, including the automatic error fixes it runs before it replies. 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, when there is one.
`started_at`	When the builder 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.

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

status is one of:

finished: the builder replied and has nothing pending.
waiting_for_user_input: the builder 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 builder was interrupted, for example by a restart. It continues in a new turn whose continues_message_id is this turn’s message_id.

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.

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
`builder.turn_started.v1`	builder.turn_started.v1.json
`builder.turn_ended.v1`	builder.turn_ended.v1.json
`webhook.test.v1`	webhook.test.v1.json

A published schema never changes. 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 one to endpoints that selected it.

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.

Base44 APIs

Apps API (Beta)

Workspace API (Beta)

Superagents API (Beta)

Monitoring API

Audit Logs API

Outbound webhooks

The envelope

App events

Example: app.created.v1

Builder events

The activation test

JSON Schemas

​The envelope

​App events

​Example: app.created.v1

​Builder events

​The activation test

​JSON Schemas

The envelope

App events

Example: app.created.v1

Builder events

The activation test

JSON Schemas