[Bug] Paid Tier 1 project incorrectly using Free Tier quota — 429 limit: 0 on gemini-3.1-flash-lite-image

Gemini API
1

Subject: Gemini API Paid Tier 1 incorrectly enforced as Free Tier — 429 quota limit 0

Hello Google Cloud / Gemini API Support,

I am experiencing what appears to be a billing tier / quota synchronization issue with the Gemini API.

My Google AI Studio billing account is active and currently shows:

  • Billing Tier: Paid Tier 1

  • Billing Plan: Prepay

  • Available prepaid balance: approximately $34

  • Project: dgegh

Google AI Studio’s Rate Limits page also confirms that the project is on Tier 1.

For Nano Banana 2 Lite / Gemini 3.1 Flash Lite Image, AI Studio shows paid Tier 1 limits of approximately:

  • RPM: 150

  • TPM: 100K

  • RPD: 1K

However, every generateContent request to:

gemini-3.1-flash-lite-image

returns:

HTTP 429 RESOURCE_EXHAUSTED

The quota violation specifically references:

generate_content_free_tier_requests
limit: 0

and:

generate_content_free_tier_input_token_count

This indicates that the API request is being evaluated against Free Tier quota even though the project and billing account are shown as Paid Tier 1.

Troubleshooting already completed:

  • Confirmed the API key loaded by the production application matches the current API key.

  • Confirmed the API key and PM2 environment match using SHA-256 fingerprints.

  • Confirmed GET /v1beta/models returns HTTP 200.

  • Confirmed models/gemini-3.1-flash-lite-image is returned by the Models API for this API key.

  • Confirmed the model appears in the AI Studio Tier 1 Rate Limits dashboard.

  • Created/replaced the API key and reproduced the same behavior.

  • Confirmed the billing account has an available prepaid balance.

  • Confirmed the issue is not caused by application code or network connectivity.

Could you please check the backend billing/quota assignment for this project and confirm whether the project’s Paid Tier 1 status has been correctly provisioned for Gemini API generateContent requests?

It appears that the project is displayed as Paid Tier 1 in AI Studio but is still being routed/enforced against Free Tier quota metrics.

I can provide the Google Cloud Project Number, Billing Account ID, complete 429 response, API request timestamps, and screenshots privately if required.

Please do not request the API key itself; I can provide the Project Number and other non-secret identifiers.

Thank you.

2

I am having the same issue, did you find a solution to this?

3

Hello @Reo_R ,

One of the reasons this error occurs is when your project which is used to create the API key is not linked to the billing account even though the billing account is active. In GCP, verify that your project is linked to your active billing account.

If you still face issues, Please share your GCP Project Number and Billing account ID privately via DM. To send a DM(direct message), click on my profile picture or name, and then select the Message button.