Gemini 4 Carbon API: Pricing, Code Examples, and Carbon vs Argon

• Published: November 11, 2026
• Last checked: November 11, 2026
• Status: Active; available in the default group

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Key facts

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Pricing

• Google’s introductory price runs through November 30, 2026. From December 1, Google charges $4 input and $20 output. LaoZhang API bills at Google’s price and will move on the same date, with a notice in Announcements beforehand. Gemini 4 Argon changes on the same day by the same amount.
• Thinking tokens are billed at the output price. A request with 46 input tokens, a 7-token answer and 188 thinking tokens is billed for 195 output tokens, about $0.002.
• Cache reads come from Google’s implicit caching. When you resend the same prefix of 4,096 tokens or more, the cached part is billed at the cache price automatically; no extra parameter is needed.
• Token usage and the charge for every request are in the usage logs. Current prices live in Models & Pricing.

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Gemini 4 Carbon vs Gemini 4 Argon

• Both models share the same per-token price, context window, built-in tools and request format. Switching is a one-word change to model.
• Google notes that Carbon spends more thinking tokens per turn. The same request usually produces more output tokens on Carbon, so it costs more in total and takes longer.
• Reach for gemini-4-carbon on hard coding, debugging, math and science problems. Stay on gemini-4-argon for work it already handles well, and for high-volume or cost-sensitive traffic. Before switching production traffic, run your own samples through both and compare quality, latency and the token counts in the usage logs.

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Code examples

export LAOZHANG_API_KEY="your-laozhang-api-key"

curl https://api.laozhang.ai/v1/chat/completions \
  -H "Authorization: Bearer $LAOZHANG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gemini-4-carbon",
    "reasoning_effort": "high",
    "messages": [
      {"role": "user", "content": "In three sentences, explain what a database index is and why it slows down writes."}
    ]
  }'

curl "https://api.laozhang.ai/v1beta/models/gemini-4-carbon:generateContent" \
  -H "Authorization: Bearer $LAOZHANG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [
      {"role": "user", "parts": [{"text": "In three sentences, explain what a database index is and why it slows down writes."}]}
    ],
    "generationConfig": {
      "thinkingConfig": {"thinkingLevel": "high"}
    }
  }'

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["LAOZHANG_API_KEY"],
    base_url="https://api.laozhang.ai/v1",
    timeout=600.0,
    max_retries=0,
)
response = client.chat.completions.create(
    model="gemini-4-carbon",
    reasoning_effort="high",
    messages=[{"role": "user", "content": "In three sentences, explain what a database index is and why it slows down writes."}],
)
print(response.choices[0].message.content)
print(response.usage)

• OpenAI-compatible responses put the answer in choices[0].message.content and the thinking token count in usage.completion_tokens_details.reasoning_tokens.
• Gemini-native responses put the answer in candidates[0].content.parts[].text and the thinking token count in usageMetadata.thoughtsTokenCount; modelVersion reads gemini-4-carbon.
• Code that already calls Gemini 4 Argon only needs gemini-4-argon replaced with gemini-4-carbon in model or the URL. The API key and other parameters stay the same.
• For images, streaming and multi-turn requests in the native format, see Gemini protocol. For tools, see Function calling.

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Thinking levels

• Leave it out and Google’s default, medium, applies.
• The Gemini-native endpoint rejects minimal; the lowest level is low.
• Higher levels produce more thinking tokens, so they cost more and take longer. Use low for simple questions and high for hard ones.
• Google states that Gemini 4 Carbon ignores temperature, top_p and top_k. Sending them does not cause an error, but they have no effect.

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Who this affects

• Applies to: projects that call Gemini through LaoZhang API for complex coding, debugging, math and science reasoning, or multi-step agent work. Any default-group API key with the Usage first or Usage-based billing mode can call it.
• Not affected: no existing model changed with this launch. gemini-4-argon, gemini-3.8-flash and the other Gemini models keep working, and existing integrations need no changes.

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FAQ

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What is the Gemini 4 Carbon model ID?

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Do I need a Google account or a paid Gemini API plan?

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Will the price change after December 1?

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Is Gemini 4 Carbon or Gemini 4 Argon better value?

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Does it accept images, PDFs, audio or video?

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What if long requests time out?

• OpenAI-compatible: add "stream": true to the request.
• Gemini native: call streamGenerateContent?alt=sse instead.

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Sources and related pages

• Google: Gemini 4 Carbon model page: model ID, context window, output limit, input types, thinking levels and supported tools.
• Google: Gemini API pricing: introductory price, the price from December 1, and implicit caching.
• Google: Gemini API changelog: general availability on November 10, 2026.
• Models & Pricing: current LaoZhang API prices.
• Gemini 4 Argon launch announcement
• Text generation API: protocols and common models
• Gemini protocol: generateContent
• LaoZhang API announcements