gemini-4-argon) is the flagship Google announced on September 30, 2026 and the first model of the Gemini 4 family. Google positions it for long-horizon software engineering, enterprise knowledge work such as legal and finance, and cybersecurity defense. It opened to the paid tier of the Gemini API on October 13, and APIYI is among the first platforms with access. Both the Gemini native and OpenAI-compatible endpoints are open, and we ran 400+ test calls before launch with gemini-3.1-pro-preview as the reference.
gemini-4-argon, available in the default and svip groups, served from official Google capacity. Pricing currently follows Google’s limited-time promotional rate of $2 input / $10 output per 1M tokens, valid through November 30, 2026. From December 1, Google’s price goes to $4 / $20, and APIYI will adjust at the same time.Key Advantages
Same accuracy, far less thinking
1M context, verified
Top scores on Google's benchmarks
Both endpoints, full tool chain
Model Information
Official Benchmarks
All figures below are published by Google (theblog.google posts of 2026-09-30 and 10-13) and have not been reproduced by APIYI:
Tested Capability Matrix
Tested by APIYI on October 13–14, 2026 (UTC+8). In the compatibility suite, every case was fired at the same time asgemini-3.1-pro-preview:
Pricing
Thinking Control
Google’s default level ismedium. Results on one combinatorics proof (native endpoint):
Caching
Google says Argon has implicit caching on by default and does not support explicit caching. In APIYI’s tests the hit rate is low: most repeated same-prefix requests did not hit, and hits showed up only on some requests (a 70K-token prefix sent four times hit about 68K tokens on the last two, billed at the cache rate).Code Examples
Gemini Native Format (recommended, most complete)
x-goog-api-key header (the official SDK default) or Authorization: Bearer. Both take your APIYI sk- key.OpenAI-Compatible Format (no changes to existing code)
Migration Guide
Migrating from gemini-3.1-pro-preview
Migrating from gemini-3.1-pro-preview
thinkingBudget and use thinkingLevel instead, or you may get a 400; (2) stop relying on temperature, topP and topK, since Google says Argon ignores custom sampling values (passing them does not error in our tests, but there is no guarantee they apply); (3) remove explicit caching calls (cachedContents). On price, during the promotional period input is slightly higher than 3.1 Pro and output slightly lower, and because Argon thinks much less, most tasks cost less overall.How long should the client timeout be?
How long should the client timeout be?
Can it output more than 64K tokens?
Can it output more than 64K tokens?
background=True on the Interactions API, or the client-side continuation protocol on generateContent. The APIYI gateway does not support the Interactions API yet (it returns 404), so design around the default 65,536-token output limit and split very long outputs across several turns.What should I watch for in multi-turn tool calls?
What should I watch for in multi-turn tool calls?
thoughtSignature in its parts. Do not edit or rebuild it yourself. The official google-genai SDK handles this automatically when you use a chat session or pass back response.candidates[0].content. On the OpenAI-compatible endpoint the gateway handles signatures, so standard tool_calls / tool messages are enough; two-turn calls passed 10/10 in our tests. If you occasionally get a 400 Invalid thought signature or Corrupted thought signature, resend the same request once; there is no need to change it.How do I connect Codex and similar clients?
How do I connect Codex and similar clients?
/v1/chat/completions and the Gemini native endpoint only. /v1/responses is not supported (it returns contents is required). For clients such as Codex that default to the Responses API, configure the provider to use the chat protocol (wire_api = "chat").Should I use responseSchema or responseJsonSchema for structured output?
Should I use responseSchema or responseJsonSchema for structured output?
responseJsonSchema (standard JSON Schema). responseSchema is an OpenAPI subset and does not accept fields such as additionalProperties; including them may return a 400 Unknown name "additionalProperties". On the OpenAI-compatible endpoint, use response_format: {"type": "json_schema", ...}.Do I need a Google API key for the native endpoint?
Do I need a Google API key for the native endpoint?
sk-) in the x-goog-api-key header. With the official google-genai SDK, just set base_url to https://api.apiyi.com.Which capabilities are native-only?
Which capabilities are native-only?
safetySettings, enforced stopSequences, and controllable thinking levels are only available on the Gemini native endpoint. The OpenAI-compatible endpoint covers the common features (chat, streaming, function calling, JSON Schema, vision), but stop is not enforced and reasoning_effort has little visible effect.