Tier 1 Postpay project returns 429 "prepayment credits are depleted" — fresh key did not fix

Gemini API
1

My Gemini API project returns 429 RESOURCE_EXHAUSTED on every generateContent
call, with message “Your prepayment credits are depleted,” even though the
project is on Tier 1 Postpay with an active, linked Cloud billing account.

Project ID: graphify-49651..
Project number: 5395179577…
Billing: paid account (upgraded from free trial 25 May 2026), Tier 1 Postpay,
linked and active in Cloud Console.

What works:

  • API key authenticates fine
  • models.list / ListModels returns all models

What fails:

  • generateContent on gemini-2.5-flash-lite returns 429 RESOURCE_EXHAUSTED
    “Your prepayment credits are depleted”

What I have tried:

  • Generated a brand-new API key after billing was active — same 429
  • Confirmed billing account is active and linked to the project in Cloud Console

This looks like the postpay-vs-prepay billing sync issue others have reported
recently. Please correct the project’s billing state so postpay works without
requiring a manual prepay top-up. Thank you.

2

Hi @Darvintiran_Subraman ,

I’m not certain from your message whether your existing balance is in credits. If so, you’ll need to make a small prepayment to activate the prepayment account and use the credits