Violating unclear limits (429 HTTP error)

Hi all!

I use Gemini API to classify some texts. I use model gemini-2.5-flash (due to their great free tier allowing large context). The instruction is approximately 189k tokens, a decision usually add up to 5-20k tokens.

Approximately two weeks ago I started to receive HTTP error 429. It is unclear to me why. As I wrote above my prompts are shorter than the limit on tokens per minute (250k tokens). However, there is no error for shorter prompts. So my guess is that my prompts violate the limit on tokens per minute. However the reasons are unclear. Is it some shadow ban or something (I received no e-mails about cutting of the limits)?

I would genuinely appreciate any advice on how to deal with this matter. Should you need some more information, please, let me know.

If it helps I attach extract of the R code I use:

Set model and create link to connect with

model ← “gemini-2.5-flash”
model_query ← paste0(model, “:generateContent”)
url ← paste0(“https://generativelanguage.googleapis.com/v1beta/models/”, model_query)

Create instruction

instruction_text ← readtext(“instruction.docx”)$text

Extract text to be classified

decision ← readtext(“decisionXXX.docx”)$text

send_request ← function(link, prompt) {
response ← request(link) |>
req_url_query(key = api_key) |>
req_headers(“Content-Type” = “application/json”) |>
req_body_json(list(
contents = list(
parts = list(
list(text = decision)
)
),
generationConfig = list( t
temperature = 0
),
system_instruction = list(
parts = list(
list(text = instruction_text)
)
)
)
) |>
req_perform()

output ← response |>
resp_body_json()

output ← output$candidates[[1]]$content$parts[[1]]$text
}

Hi @IceLV Welcome to the community
Error 429 usually means you are sending too many requests per minute with the free tier Gemini API. Does this error occur with high frequency?
I will also confirm with the team if any limits have been added. Could you please specify the region?
Please check this Rate limits  |  Gemini API  |  Google AI for Developers and if needed request a quota increase.
Thank you