Hi @TAEIN_WORKS, Here are the clarifications regarding the HTTP 503 and 429 errors on the Free Tier:
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HTTP 503 (Service Unavailable): On Gemini 3.8 Flash, 503 errors are due to our services being temporarily overloaded. Please see this pinned post for suggestions on how to handle this.
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HTTP 429 (Too Many Requests): We recently made some backend updates to ensure that all 429 errors come with a description field which properly explains the cause. We recommend scanning your logs for these. While a lot of pertinent information is currently available in the AI Studio Usage, Rate Limit & Billing pages, we’re working to make the cause of 429 errors easier to find in AI Studio. Please see below for advice on specific categories of 429 errors.
Spend cap exceededWe return 429 errors if a spend cap is exceeded.
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Please see Billing account tier spend caps for more information.
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You should also check whether you set a Project spend cap.
Rate limits
Multiple different types of rate limits can result in 429 errors. You should check the AI Studio Rate Limits page to see details of these. Notes:
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Be sure to select the applicable project & time range.
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Take special care to check the Search grounding & Map grounding limits further down the page
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If you’re running into limitations from RPM or TPM limits, consider implementing backoff and retry with a long maximum delay (our SDKs support this through retry config).
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