Paid Tier 1 / Prepay project receives Free Tier quota limit=0 for gemini-3.1-flash-image

Gemini API
1

Hello,

I am using the Gemini API with a project that is shown in Google AI Studio as Tier 1 / Prepay, with an active prepaid credit balance.

However, requests to gemini-3.1-flash-image consistently return HTTP 429.

The complete error includes:

generativelanguage.googleapis.com/generate_content_free_tier_input_token_count
limit: 0

and:

generativelanguage.googleapis.com/generate_content_free_tier_requests
limit: 0

The error also identifies the model as:

gemini-3.1-flash-image

Google AI Studio shows that my project is Tier 1 / Prepay, billing is active, and prepaid credit is available. The Rate Limits dashboard also does not show normal RPM/TPM limits being exhausted.

It appears that the Gemini API backend may be applying Free Tier quota (limit: 0) to this image model even though the project is on Paid Tier 1.

SDK: google-genai 2.22.0

I can provide my Project ID privately to Google staff if required.

Could you please check whether Paid Tier provisioning/billing for this project and gemini-3.1-flash-image is correctly enabled?

Thank you.

2

Hello @nao1 ,

Can you verify the following steps:

  1. Confirm API Key Project: In Google AI Studio, navigate to Get API key and ensure the key used in the SDK call is created directly under the Paid/Prepay GCP Project (and not under a separate/default Free Tier project).

  2. Generate a Fresh Key: If billing was enabled recently, generate a new API key within that specific project to ensure the updated quota permissions propagate immediately. If you still face the error, let us know.