Is Gemini 4 Argon Free?

No. As of October 15, 2026, Gemini 4 Argon has no free tier. Google’s Gemini API pricing page states this directly: “Gemini 4 Argon is not available on the Free tier or on the Google AI Pro plan.” That statement applies to API access. Since Argon became generally available on October 13, every confirmed route to it has been paid: the paid Gemini API tier at $2/$10 per 1M tokens through November 30 and $4/$20 afterward, the Gemini app and Search for Google AI Pro and Ultra subscribers, and Google Antigravity for Ultra subscribers.

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This guide explains every access route, its cost, the “free Argon” claims that do not hold up, the cheapest way to test the model, and the free Gemini model you can use while building your integration. For background, see what Gemini 4 Argon is; for the rollout from Fairwind-only access to general availability, see the Gemini 4 Argon release date. Apidog lets you develop against a free model first and switch to Argon by changing one variable.

Every route, and whether it gets you Argon

Route	Cost	Gets Argon?	Notes
Gemini API, paid tier	$2/$10 per 1M tokens through Nov 30, then $4/$20	Yes	Model ID gemini-4-argon, stable
Gemini API, free tier	$0	No	“not available on the Free tier”
Gemini app, Google AI Pro	$19.99 a month	Yes	Also available in Search
Gemini app, Google AI Ultra	$99.99 or $199.99 a month	Yes	Also in Search and Antigravity
Gemini app, free plan	$0	No	Google named Pro and Ultra only
Google AI Plus	$4.99 a month	Not named	Absent from Google’s GA announcements
Google Antigravity	Ultra plan	Ultra only	Pro and free plans not named
Cursor	$2/$10 per 1M tokens in Cursor’s listing	Yes	Added October 13
OpenCode Go	“$60 usage for $10 til Nov 30”	Yes	Low cost, not free
Gemini CLI	Paid API key only	Not confirmed	No consumer accounts since 2026-06-18
Fairwind Program	Not stated	Yes, since Sep 30	Vetted cyber defenders only
“Free Argon API” sites	Varies	Unverified	Google offers no free Argon tier
gemini-3.8-flash free tier	$0, rate-limited	No	The free Gemini API model you can use

The paid routes that get you Argon

The paid Gemini API

Argon appears on the Gemini API models page as gemini-4-argon, a stable model without a -preview suffix. Your project must use a paid tier, starting with Tier 1, which requires linked billing. Google says paid-tier content is not used to improve its products.

Pay-as-you-go pricing makes a test call inexpensive. With the rates available through November 30, a 2,000-token prompt and a 1,000-token answer cost:

0.002M × $2 + 0.001M × $10 = $0.014

That is cheap, but it is not free. Argon’s thinking tokens are billed as output, so the actual cost of a response can be higher than its visible text suggests.

Google AI Pro and Ultra

Google’s Gemini app announcement says, “Google AI Pro and Ultra subscribers can now access Gemini 4 Argon.” Sundar Pichai’s launch-day post adds Search access for both plans and Google Antigravity access for Ultra.

When Google’s US plans page was checked on October 1, AI Pro cost $19.99 per month. AI Ultra started at $99.99 per month with 5x Pro’s usage limits, or $199.99 per month with 20x. Google has not published per-plan Argon message limits, so Pro and Ultra should not be assumed to have the same allowance. These subscriptions are consumer plans, not API keys; the API pricing page specifically excludes the Google AI Pro plan from Argon API access.

Cursor and OpenCode Go

Cursor added Argon on October 13 and lists it at $2 per 1M input tokens and $10 per 1M output tokens, matching Google’s current rate. OpenCode added it to OpenCode Go on October 14 with the promotion “$60 usage for $10 til Nov 30.”

Both can reduce the cost of trying Argon, but neither provides free access.

Routes that do not get you Argon free

The Gemini API free tier

The Gemini API free tier still serves other models, but Argon is not one of them. An API key from a project without linked billing will not provide Argon access.

Fairwind Program

Argon launched on September 30 for selected Fairwind Program partners. Fairwind is Google’s limited-access program for vetted cyber defenders, including governments, critical infrastructure operators, and core technology platforms. It requires background checks on the applying organization and phishing-resistant MFA. Google has not stated whether Argon access through Fairwind is billed.

Fairwind was never a consumer route, and since general availability it is no longer required to use Argon.

Gemini CLI

Since June 18, 2026, Gemini CLI no longer serves Google AI Pro, Ultra, or free users. It works only with paid Gemini API or Agent Platform keys. Argon support in Gemini CLI has not been confirmed, and it would not be free in any case.

“Free Gemini 4 Argon API” sites

Google does not offer free Argon API access. Treat any site promising a free Argon API as unverified, and keep your API keys, source code, and customer data away from services that cannot be traced back to Google or a known tool vendor.

Wiz Scan for Good

Google’s launch post says Argon, used through Wiz Scan for Good, found a critical vulnerability in healthcare software used by hospitals. Google describes Scan for Good as a Wiz program “dedicated to protecting critical public infrastructure for free.”

That “free” describes what Wiz offers to infrastructure owners. It is not public Argon access.

What Argon costs

These are the Standard rates listed on Google’s pricing page, per 1M tokens, as of October 15, 2026:

Item	Through Nov 30, 2026	From Dec 1, 2026
Input	$2.00	$4.00
Output, thinking included	$10.00	$20.00
Cached input, implicit	$0.10	$0.20
Batch or Flex input / output	$1.00 / $5.00	$2.00 / $10.00

Caching is implicit only. Prompts of 4,096 tokens or more receive a 95% discount on cache hits, while explicit caching is not supported.

The only free line item is Search grounding: 5,000 free requests per month shared across Gemini 3 and later models, followed by $14 per 1,000 requests. That is free grounding on a paid model, not free model tokens. For a detailed cost walkthrough, see the Gemini 4 Argon pricing breakdown.

The free Gemini you can use today

Gemini 3.8 Flash on the API free tier

gemini-3.8-flash is Google’s stable Flash model and has a free tier in Google AI Studio and the Gemini API. It accepts 1,048,576 input tokens and returns up to 65,536 output tokens. It supports the same thinking levels as Argon—low, medium, and high—with medium as the default, which helps keep a later model switch small.

The free tier is rate-limited; current per-model limits are available at aistudio.google.com/rate-limit. Google says free-tier data is “used to improve our products,” so avoid sending confidential code or customer data through it. When you outgrow the free tier, paid pricing is $0.75/$3.75 per 1M tokens through December 31, 2026, then $1.50/$7.50.

For setup instructions, see using Gemini 3.8 Flash for free. To decide which requests belong on which model, read Gemini 4 Argon vs Gemini 3.8 Flash.

The Gemini app free plan

For chat rather than API development, the free Gemini app plan does not include Argon. When Google’s US plans page was checked on October 1, the free plan listed Gemini 3.6 Flash with varying access to Gemini 3.1 Pro.

See how to use Gemini for free for a broader look at free Gemini surfaces. If you are comparing other frontier models, the same question is covered in is Claude Opus 5.5 free.

Build free on Flash, switch to Argon with one variable

Put the model name in an environment variable and develop against gemini-3.8-flash using a free-tier key. After linking billing, point the same request at gemini-4-argon:

MODEL="${GEMINI_MODEL:-gemini-3.8-flash}"   # GEMINI_MODEL=gemini-4-argon on a paid key

curl -s "https://generativelanguage.googleapis.com/v1beta/interactions" \
  -H "x-goog-[REDACTED CREDENTIAL] \
  -H "Content-Type: application/json" \
  -d "{
    \"model\": \"$MODEL\",
    \"input\": \"List the breaking changes in this API changelog.\",
    \"generation_config\": {\"thinking_level\": \"medium\"}
  }"

The request follows the shape of Google’s own Argon REST example. Before switching, check three items from Google’s migration checklist in the Argon developer guide:

• Remove explicit caching: cachedContents, caches.create, and cached_content are not supported because Argon uses implicit caching only.
• Remove temperature, top_p, and top_k; Argon ignores them.
• Review max_output_tokens and increase client timeouts because difficult Argon prompts can take minutes.

In Apidog, store GEMINI_API_KEY and GEMINI_MODEL as environment variables, save the request with {{GEMINI_MODEL}} in the body, and add assertions for the response status and token counts. Keep one environment pointing to Flash and another pointing to Argon, then run the same saved request in both. That gives you a direct cost and quality comparison before moving production traffic.

FAQ

Is Gemini 4 Argon free?

No. As of October 15, 2026, it is not available on the Gemini API free tier, and the Gemini app routes require Google AI Pro or Ultra.

Can I use Gemini 4 Argon in the Gemini app for free?

No. Google names AI Pro, at $19.99 per month, and AI Ultra subscribers only.

Does Google AI Pro include Argon?

In the Gemini app and Search, yes. For the API, no: the pricing page says Argon is not available on the Google AI Pro plan. Antigravity access is named for Ultra only.

What is the cheapest way to try Argon?

Use pay-as-you-go billing on the paid Gemini API, where a short test call costs about one and a half cents. OpenCode Go’s promotion—$60 of usage for $10 until November 30—is another low-cost option.

Will Argon get a free tier?

Google has not announced one. Its previous top Pro model, Gemini 3.1 Pro Preview, also has no free API tier.

Is Fairwind still the only way in?

No. Fairwind partners received Argon first on September 30. Since October 13, any project on a paid API tier can call it. The release date guide covers each rollout stage.

Start free, keep the switch to one variable

You cannot use Argon for free, but you can build the integration around it for free. Download Apidog, point a saved request at gemini-3.8-flash on the free tier, and keep the model name in GEMINI_MODEL. When you link billing, set it to gemini-4-argon, remove unsupported caching and sampling parameters, and rerun your tests. Argon’s price doubles on December 1, so complete your comparison before then if cost is the deciding factor.