Unexpected Gemini API charges via Firebase API key — request for review

Project: harmonea-a873b (681107406442)
Billing account: 015CDD-C0C8DF-69…
Issue: Unauthorized Gemini API charges of ~CA$2,918 on or around May 3, 2026

Evidence:

  • Single-day burst totalling CA$2,918 with no preceding or following usage
  • Project was automatically flagged by GCP abuse detection — REINSTATE
    audit event at 2026-04-30T19:14:55Z (resource type
    abuseevent.googleapis.com/Location, action=REINSTATE)
  • Zero application-level Gemini calls logged in Cloud Logging for the
    spike window (Cloud Run / Cloud Functions had no traffic that could
    account for the spend)
  • The API key in scope at the time was a Firebase auto-generated
    Browser key (UID 970e24ea-1d3a-4116-9c87-3a2da2709c16) whose
    restrictions allowed firebasevertexai.googleapis.com — the likely
    bypass path. This restriction has now been removed and the key has
    been rotated.
  • Tier 2 monthly cap (CA$5,000) was triggered by this single burst,
    pausing service for legitimate users.

Requesting: full credit/reversal of the ~CA$2,918 charge. We have
implemented mitigation: key rotation, restriction tightening, and
Secret Manager audit logging.

Hi @Yousef_Rastgar ,

I’m sorry to hear this. Unfortunately we can’t help you hear on the forum. To get this resolved, please contact cloud billing.