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Gemini 4 Carbon API Pricing and Day 0 Support on LiteLLM

Gemini 4 Carbon on LiteLLM: the LiteLLM and Gemini 4 Carbon lockup, then Gemini 4 Carbon selected in the LiteLLM model list next to Gemini 4 Argon, Gemini 3.8 Flash and Gemini 3.5 Flash.
Published:
Misbah SyedDevRel Engineer, LiteLLMMateo WangAI Engineer, LiteLLMKerry LuSoftware Engineer, LiteLLM

LiteLLM now supports Gemini 4 Carbon on Day 0. Use it on Google AI Studio and Gemini Enterprise Agent Platform (formerly Vertex AI) through the LiteLLM AI Gateway, with spend, rate limits and logs in one place.

Gemini 4 Carbon pricing​

Launch prices per 1M tokens, until November 30, 2026:

  • Input: $2.00 / MTok
  • Output: $10.00 / MTok. Thinking tokens bill as output.
  • Cache read: $0.10 / MTok. Carbon supports implicit caching only.
  • Batch and Flex: $1.00 input and $5.00 output
  • Priority: $3.60 input and $18.00 output

On December 1, 2026, these prices double to $4.00 input, $20.00 output and $0.20 cache read. On Gemini Enterprise Agent Platform, regional endpoints cost 10% more than global.

Prices on every provider: https://models.litellm.ai/models/gemini-4-carbon

Use Gemini 4 Carbon with LiteLLM​

No upgrade needed: open Price Data under Models + Endpoints in the UI and click Reload Price Data (or POST /reload/model_cost_map), on v1.76.0 and above.

1. Setup config.yaml

model_list:
  - model_name: gemini-4-carbon
    litellm_params:
      model: gemini/gemini-4-carbon
      api_key: os.environ/GEMINI_API_KEY

2. Start the proxy

docker run -d \
  -p 4000:4000 \
  -e GEMINI_API_KEY=$GEMINI_API_KEY \
  -v $(pwd)/config.yaml:/app/config.yaml \
  ghcr.io/berriai/litellm:v1.106.2 \
  --config /app/config.yaml

3. Test it!

curl --location 'http://0.0.0.0:4000/chat/completions' \
--header 'Content-Type: application/json' \
--header "Authorization: Bearer $LITELLM_KEY" \
--data '{
  "model": "gemini-4-carbon",
  "messages": [
    {
      "role": "user",
      "content": "what llm are you"
    }
  ],
  "reasoning_effort": "low"
}'

LiteLLM sends reasoning_effort to Carbon as its thinking_level.

FAQ​

How much does Gemini 4 Carbon cost?​

Until November 30, 2026, it costs $2.00 per 1M input tokens and $10.00 per 1M output tokens, the same as Gemini 4 Argon. On December 1, the prices change to $4.00 and $20.00.

Is Gemini 4 Carbon priced the same as Gemini 4 Argon?​

Yes. Both cost $2.00 / $10.00 per 1M tokens until November 30 and $4.00 / $20.00 from December 1.

What is the context window of Gemini 4 Carbon?​

1,048,576 tokens for input, thinking and output together. Google returns up to 65,536 output tokens per synchronous request, and LiteLLM continues past that cap the same way it does for Argon.

Which thinking levels does Gemini 4 Carbon support?​

low, medium and high, with medium as the default. Set it with reasoning_effort.

Does Gemini 4 Carbon support context caching?​

Implicit caching only, from 4,096 prompt tokens. Explicit caching is not supported.

Is Google Search grounding free on Gemini 4 Carbon?​

The first 5,000 queries a month are free, shared with Gemini 3 and newer models, then $14 per 1,000 queries. LiteLLM tracks the shared allowance as of PR #50951.

How do I call Gemini 4 Carbon with an OpenAI-compatible API?​

Add gemini/gemini-4-carbon to your LiteLLM config. Then send a standard /chat/completions request to the proxy with "model": "gemini-4-carbon".

Feedback​

Questions and feedback go in GitHub discussion #50970.

References​