Use Background Triggers in Firebase Cloud Functions

You’ve used Firebase Cloud Functions — But did you know they support background triggers?

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Most devs think of Firebase Cloud Functions as HTTP endpoints — but the real power lies in background triggers. Learn how to work with them in this article.

What’s a background trigger?

It’s a function that runs automatically in response to Firebase events — no request required.

Examples

• A user signs up (Firebase Authentication)
• A document is written (Firebase Cloud Firestore)
• A file is uploaded (Firebase Cloud Storage)

Code examples

exports.logNewUser = functions
    .auth
    .user()
    .onCreate((user) => {
  console.log(`New user signed up: ${user.uid}`);
});

This code registers a function that logs every new sign-up. You can extend this to:

• Add users to Firestore
• Send welcome emails
• Trigger analytics workflows

exports.logDocumentChanged = functions
    .firestore
    .document("my-collection/my-id")
    .onWrite((change, context) => {…