Use Gemini 4 Carbon for root-cause debugging, dense documents and security review. Prepare a native Gemini request here, then continue on SeedRouter to check access and run it.
Gemini 4 Carbon service belongs on SeedRouter. reAPI provides this guide and request editor, not model access, API keys or billing.
Prepare a Gemini 4 Carbon request in SeedRouter’s native Gemini format. Edit parameters locally, inspect the JSON, then continue on SeedRouter.
POST /v1beta/models/gemini-4-carbon:generateContent · SeedRouter
Request body preview only. Edit structured fields as JSON; additional fields stay in the request.
{
"contents": [
{
"role": "user",
"parts": [
{
"text": "A background job sometimes sends the same invoice email twice after a deploy. List the most likely root causes, explain how to confirm each one from logs and code, then propose a fix and the tests to ship with it."
}
]
}
],
"generationConfig": {
"thinkingConfig": {
"thinkingLevel": "medium"
}
}
}Copy the JSON, open SeedRouter, and send it with the same method. reAPI does not submit or bill this model.
This link opens the Gemini 4 Carbon page on SeedRouter. Check current access and service terms there before submitting.
Gemini 4 Carbon (gemini-4-carbon) is Google’s strongest reasoning model in the Gemini API, available to paid developers since November 10, 2026. It reads text, images, video, audio and PDF, returns text, and shares one 1,048,576-token window across input, thinking and output. Compared with Gemini 4 Argon, it spends more thinking tokens per turn to explore and check its work, so each answer takes longer and uses more tokens. This page helps you decide when Gemini 4 Carbon is worth that trade and prepare a request for SeedRouter; it does not provide a reAPI endpoint.
Real-world workflows and production use cases you can build and ship with this model.
Give Gemini 4 Carbon the failing behavior, the logs and the code paths involved. Ask it to rank hypotheses, explain how to confirm each one, and propose a fix with tests you can run.
Prepare a Gemini 4 Carbon debug request
Send PDFs, slides or spreadsheets with your question. Ask Gemini 4 Carbon to cite the passage behind each claim and follow the output schema you supply, then check those citations against the source.
Point Gemini 4 Carbon at a patch and the code it touches. Ask where the flaw could still be reached, which input would prove it, and which tests should block a regression. Treat its findings as leads to verify.
Pick low, medium or high thinking for Gemini 4 Carbon. Medium is the documented default; Google suggests testing all three and keeping the lowest level that meets your quality bar.
Build a Gemini 4 Carbon request for generateContent or streamGenerateContent from SeedRouter’s contract. Generation and thinking options each get their own control.
Inspect and copy the complete Gemini 4 Carbon JSON before leaving this page. Extra fields you add in JSON mode stay in the request.
Start with generateContent for one Gemini 4 Carbon response or streamGenerateContent for incremental output. The example prompt is a debugging task you can replace; the thinking level starts at the documented default.
OpenEdit contents, tools and generation options, or switch to JSON mode for the full body. On non-streaming Gemini 4 Carbon calls, keep maxOutputTokens at 32,768 or lower unless you send a continuation token.
OpenOpen the Gemini 4 Carbon page on SeedRouter and check access for your account. Paste your JSON into its editor or send it from your own client. Results and charges happen there; nothing runs from this page.
OpenSend text, images, video, audio and PDF in one request. Output is text only: Gemini 4 Carbon does not generate images or audio.
Input, thinking and output share 1,048,576 tokens. Default synchronous output is 65,536 tokens; long decode with continuation tokens reaches up to 1M.
Low, medium and high trade depth for token use and latency. Temperature, topP and topK are ignored, so tune the thinking level instead.
Google documents function calling, code execution, Search and Maps grounding, URL context, file search and computer use. Your application still runs its own functions.
Gemini 4 Carbon applies implicit caching to prompts of at least 4,096 tokens. Explicit cached contents are not supported, so remove cachedContent from older requests.
Supply a response schema and check what comes back. Google lists structured outputs as supported; your application should still validate each result.
Common questions about this model.
Google frames the two as a depth-versus-speed choice on the same request format. Gemini 4 Carbon is not a larger Argon: both share the window and tools, while Carbon spends more thinking on each turn.
Based on Google’s Gemini API documentation checked November 11, 2026. This compares documented specifications, not measured performance or reAPI service availability. Gemini 4 Carbon access is directed to SeedRouter.
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Prepare your prompt here, keep a copy of the JSON, and check Gemini 4 Carbon access on SeedRouter. Account setup, model execution and usage happen there.
