Firebase Unexpected Bill on Blaze Plan
Quick answer
Budget alerts on Blaze only send emails; they do not stop usage. Find the top-cost service in Cloud Billing reports, fix the loop or traffic spike, then add alerts, spend caps where available, or downgrade to Spark.
Most likely fix: Find the cost source
How to fix it
Try these in order — the most common fix is first.
1. Find the cost source
- Google Cloud console > Billing > Reports, group by SKU
- Check Firestore, Functions, Hosting and Auth usage in Firebase console
Did this fix it?2. Stop the leak
- Disable or fix the looping function
- Tighten Firestore rules and add App Check
Did this fix it?3. Set budgets and caps
- Create budget alerts at several thresholds
- Settings > Usage and billing > Details & settings > Service-level spend caps (Preview: Functions, App Hosting, Extensions, AI Logic)
Did this fix it?4. Last resort
- Downgrade to Spark or unlink billing; see the cancel guide
- Contact Google Cloud billing support to ask about a one-off adjustment; outcomes vary
Did this fix it?
Symptoms
A bill far above expectations, often from Cloud Functions loops, runaway Firestore reads, Hosting egress or SMS.
Why it happens
- Cloud Function triggering itself in a loop
- Real-time listeners or queries reading large collections
- Hosting or Storage egress from public files
- Phone Auth SMS costs
- Abuse of public endpoints
This guide also covers
- firebase unexpected bill
- firebase huge bill
- firebase billing surprise
- firebase budget alert not stopping
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The same problem in other apps
All billing, cancellation & refunds guides →
- Supabase 'Canceling Statement Due to Statement Timeout' (Supabase)
- MongoDB Atlas Unexpected Bill: Why It's So High (MongoDB Atlas)
Other Firebase errors
- Firestore Missing or Insufficient Permissions (permission-denied)
- Firebase auth/invalid-api-key Error
- Firebase auth/network-request-failed Error
- Firebase auth/too-many-requests Error
- Firebase auth/operation-not-allowed Error
- Firestore Quota Exceeded (resource-exhausted)
- Firebase Cloud Messaging Notifications Not Received
- Firebase Deploy Failed (Functions and Hosting)