TL;DR: What is Gemini 4 Carbon and can founders use it yet?
Gemini 4 Carbon is the model Google announced on 28 October 2026, two weeks after Gemini 4 Argon, and Google calls it its strongest model yet, built for long coding jobs and cyber defense. It tops the independent Artificial Analysis Intelligence Index at 59, one point ahead of Claude Opus 5.5. You can't use it yet: this week it goes to a small group of cyber defenders, then to more partners in Google's Fairwind Program, and developers, businesses and Gemini app users get it later, with no date. When it opens, the API starts at $2 per million input tokens and $10 per million output tokens, rising to $4 and $20 after an introductory period Google hasn't dated.
Developing story. Last updated 28 Oct 2026, 23:30 CET. We'll update this article as Google opens wider access.
Searches for "Gemini 4 Carbon" jumped 200% in the US and Germany on Wednesday, and most founders asked the same thing: can I call it from my app tonight? You can't. Here is what Google announced, which benchmarks come from outside testers, what Carbon will cost next to Argon, GPT-6 and Claude, and what to set up before day one.
What did Google announce on 28 October?
In its announcement, Google pitches Gemini 4 Carbon at two jobs. The first is long engineering work: Google says its teams have seen Carbon run for days on one task, finding and patching subtle bugs across large codebases. The second is cyber defense, the full cycle of finding a vulnerability, proving it can be exploited and writing the fix.
The rollout copies Argon's, which went to cyber defenders on 30 September and to every developer on 13 October:
- This week: a subset of cyber defenders.
- Next: more partners in Google DeepMind's Fairwind Program, which serves governments, hospitals, telecoms, energy and finance networks, big platforms and academic security labs. Google runs background checks on every applicant.
- Later: developers, businesses and consumers, "as soon as possible". No date.
- Alongside: the US government's voluntary pre-release testing of new models.
A typical SaaS startup can't apply its way in. Companies that don't qualify for Fairwind are pointed to CodeMender, Google's code security agent, running on public models. The same day, Google did open one door to small teams: the Connected Apps Platform preview, which lets startups with an API apply to put an MCP app inside Gemini and Search.
How does Gemini 4 Carbon compare with Argon, GPT-6 Astra and Claude Opus 5.5?
Google's blog post compares Carbon only with Argon. The rivals appear on the Google DeepMind model page, where Google ran most Gemini tests itself and took rival scores from OpenAI's and Anthropic's own reports. The rows measured by outside scorekeepers are the ones I trust most. Benchmarks measure known tasks, and earlier that week OpenAI and Anthropic went further: their research models produced proofs that refute the Exponential Time Hypothesis, a 27-year-old assumption in computer science.
On the independent Artificial Analysis index, Carbon leads Opus 5.5 by one point, a tie for any product decision. On security work it pulls clearly ahead, with 54.8% on ExploitGym against 42.4% for GPT-6 Astra. And it loses two rows: GPT-6 Astra and Opus 5.5 score higher on FrontierSWE 2, and Opus 5.5 leads OSWorld 2.1 by almost six points.
What does the cybersecurity focus mean for founders?
The upside first. Google says Carbon more than doubles Argon's success rate at writing secure code, scored 0.0% attack success on Gray Swan's prompt injection test (Argon: 0.7%) and makes about half as many unsupported claims as Argon.
Then the catch: defenders go first, by design. A model that writes working exploits for over half of ExploitGym's tasks helps attackers just as much, so Google hands it to vetted security teams before anyone with a credit card. Your security reviews this month still run on public models such as Argon, GPT-6 Astra or Claude. We saw the agent side of this risk in Claude Mythos 5's malicious pull request. If you are picking a public model for daily work instead, our Gemini vs ChatGPT comparison for startup operations lists current API prices.
What will Gemini 4 Carbon cost?
Carbon launches at Argon's price: $2 per million input tokens and $10 per million output tokens, cached input 95% cheaper, then $4 and $20. Argon's discount ends on 30 November 2026, per Google's Gemini API pricing page. Carbon's announcement gives no end date.
In real money: a coding agent using 20 million input and 4 million output tokens a month costs $80 on Carbon at launch, $160 later (the same as Opus 5.5) and $400 on GPT-6 Astra. Google bills Argon's thinking tokens as output, so plan on the higher number. Our pieces on AI token costs and the October AI price war cover cheaper models for routine work.
What do we know so far about Gemini 4 Carbon?
- Announced: 28 October 2026 by Koray Kavukcuoglu, Google's Chief AI Architect.
- Independent rank: #1 on the Artificial Analysis Intelligence Index v5.0 with 59.
- Access: cyber defenders this week, Fairwind partners in phases.
- Price: $2 and $10 per million tokens at launch, later $4 and $20.
- Safety: Argon's stack of training, misuse filters, prompt-injection defenses and chain-of-thought monitoring.
What we don't know yet
- Access dates for the Gemini API, AI Studio, Vertex AI, Workspace and the Gemini app.
- When the discount ends. Argon's ends on 30 November; Carbon's isn't published.
- Context window and model name. Argon has 1 million tokens and the ID gemini-4-argon. Carbon has neither published.
- Europe. The announcement doesn't mention the EU. Argon's API works in every EU country, and the Fairwind page names no regions.
- The unnamed rival. Google's Chrome team says Carbon wrote high-quality patches more than 10 times better than "another lab's large frontier model".
Timeline
- 30 September 2026: Gemini 4 Argon goes to cyber defenders in the Fairwind Program.
- 13 October 2026: Argon opens to developers worldwide at $2 and $10 (our Argon launch coverage).
- 26 October 2026: OpenAI releases GPT-6.1 Terra at $1 and $5.
- 28 October 2026: Google announces Gemini 4 Carbon for cyber defenders.
- 30 November 2026: Argon's introductory price ends.
- Date not announced: Carbon for developers, businesses and Gemini app users.
What should founders do before Gemini 4 Carbon opens?
Next steps, in the order I'd do them:
- Build the test set now. Pick 30 to 50 real, messy tasks: a bug that took a day to find, a database migration, a security review.
- Run it on Argon today. Argon costs the same as Carbon's launch price, so its scores become your baseline. On day one you swap one model name and compare.
- Keep the model switchable. Put the model name, price and a fallback in one config setting, so moving between Carbon, Argon, Claude or GPT takes one change.
- Budget at the full price. Plan with $4 and $20 and treat $2 and $10 as a bonus with an unknown end date.
- Run a security pass on your own code now. Point a public model at your login, payments and file-upload code, then repeat with Carbon and compare the findings.
- Apply to Fairwind only if you qualify, meaning you run security for a hospital, bank, telecom or public body.
- Check Europe on day one. Confirm Carbon runs from your EU account before you promise it to customers.
Are you getting customers from ChatGPT yet?
More and more traffic is coming from Perplexity, ChatGPT, Grok and other AI tools.
👉 Rank on ChatGPT
Is Gemini 4 Carbon worth waiting for?
For security products and teams running coding agents for hours, yes: it leads the independent index, beats every rival Google lists on exploit and patch tests, and launches at a fifth of GPT-6 Astra's output price. Everyone else can build on Argon today at the same price.
The bigger shift is the release pattern. Google's last two frontier models reached cyber defenders before developers, with US government testing in between. Plan for the strongest models to reach small teams after banks, governments and big platforms, and keep a better model one config change away.
FAQ: Gemini 4 Carbon
What is Gemini 4 Carbon?
Google's newest and, by its own account, strongest model, announced on 28 October 2026, built for long coding tasks and cyber defense.
Can I use Gemini 4 Carbon now?
Only as one of the cyber defenders Google picked or a Fairwind Program partner. Developers, businesses and Gemini app users get it later, with no date yet.
How much does Gemini 4 Carbon cost?
$2 per million input tokens and $10 per million output tokens at launch, then $4 and $20. Google hasn't dated the switch.
Is Gemini 4 Carbon better than Claude Opus 5.5 and GPT-6 Astra?
It scores 59 on the Artificial Analysis index against 58 for Opus 5.5 and 57 for GPT-6 Astra, and leads on cybersecurity tests. Both rivals beat it on FrontierSWE 2.
What is the Fairwind Program?
A Google DeepMind program giving vetted security teams at governments, infrastructure operators, big platforms and academic labs early access to its strongest models.
Is Gemini 4 Carbon available in the EU?
Google hasn't said. Argon works through the Gemini API in every EU country, while Carbon has no public release anywhere yet.
About the Author
Violetta Bonenkamp, also known as MeanCEO, is an experienced startup founder with an impressive educational background including an MBA and four other higher education degrees. She has over 20 years of work experience across multiple countries, including 5 years as a solopreneur and serial entrepreneur. Throughout her startup experience she has applied for multiple startup grants at the EU level, in the Netherlands and Malta, and her startups received quite a few of those. She’s been living, studying and working in many countries around the globe and her extensive multicultural experience has influenced her immensely.
