Firebase Functions V1 vs V2 Signature Mapping
This reference maps legacy V1 functions to their modern V2 equivalents. When
using the compatibility shim, you can destructure the V2 event object using the
exact parameter names from the legacy V1 trigger signature (change,
snapshot, message, object) alongside context.
Cloud Firestore
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
firestore.document().onWrite() |
onDocumentWritten() |
({ change, context }) |
firestore.document().onCreate() |
onDocumentCreated() |
({ snapshot, context }) |
firestore.document().onUpdate() |
onDocumentUpdated() |
({ change, context }) |
firestore.document().onDelete() |
onDocumentDeleted() |
({ snapshot, context }) |
Cloud Pub/Sub
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
pubsub.topic().onPublish() |
onMessagePublished() |
({ message, context }) |
pubsub.schedule().onRun() |
onSchedule() |
Access event directly |
[!NOTE] Scheduled functions moved from the pubsub namespace to the
scheduler namespace in V2.
Realtime Database
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
database.ref().onWrite() |
onValueWritten() |
({ change, context }) |
database.ref().onCreate() |
onValueCreated() |
({ snapshot, context }) |
database.ref().onUpdate() |
onValueUpdated() |
({ change, context }) |
database.ref().onDelete() |
onValueDeleted() |
({ snapshot, context }) |
Cloud Storage
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
storage.object().onArchive() |
onObjectArchived() |
({ object, context }) |
storage.object().onDelete() |
onObjectDeleted() |
({ object, context }) |
storage.object().onFinalize() |
onObjectFinalized() |
({ object, context }) |
storage.object().onMetadataUpdate() |
onObjectMetadataUpdated() |
({ object, context }) |
HTTP / Callables
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
https.onRequest() |
https.onRequest() |
Standard Express (req, res) |
https.onCall() |
https.onCall() |
Destructure ({ data, auth }) |
[!IMPORTANT] HTTP Callables do NOT use the Destructuring Shim. In V2, the
handler receives a single CallableRequest object (not a CloudEvent). You
should destructure properties like data, auth, and app directly from it.
The traditional context object is unavailable.
Auth (Blocking)
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
auth.user().beforeSignIn() |
identity.beforeUserSignedIn() |
Access event directly |
auth.user().beforeCreate() |
identity.beforeUserCreated() |
Access event directly |
[!NOTE] Auth Blocking triggers moved to the identity namespace in V2.
Cloud Tasks
| V1 Trigger |
V2 Equivalent |
Destructuring Pattern |
tasks.taskQueue().onDispatch() |
onTaskDispatched() |
Access event directly |