Gemini 4 Argon vs GPT-6 Astra vs Claude: API Pricing and Access for Developers (October 2026)

Three companies shipped top-tier models within a month of each other, and the headline price gap is large: Google's Gemini 4 Argon launched at $2 per million input tokens, while OpenAI's GPT-6 Astra and Anthropic's Claude Fable 5.1 cost $10.

If you're picking a model for something you're building, price is only half the question. The other half is whether you can actually call it today. Here's both, from each company's own announcement.

This is not a hands-on test. Every price and benchmark below comes from the vendor's own page, linked at the end.

TL;DR

Model	Company	Input / output per 1M tokens	Can you use it today?
Gemini 4 Argon	Google (Sep 30 2026)	$2 / $10 introductory, then $4 / $20	Only trusted cyber defenders (Fairwind). Paid API and Google AI Ultra next, no date
GPT-6 Astra	OpenAI (Sep 3 2026)	$10 / $50	Yes: ChatGPT paid plans + API
GPT-6.1 Sol	OpenAI	$2 / $10	Yes: API
Claude Fable 5.1	Anthropic	$10 / $50	Yes
Claude Opus 5.5	Anthropic	$4 / $20	Yes
Claude Sonnet 5.5	Anthropic	$2 / $10	Yes

What it costs per month

Take a workload of 10M input tokens and 2M output tokens a month (a busy internal tool or a small production feature). Using the list prices above:

Model	Input	Output	Monthly
Gemini 4 Argon (introductory)	10 × $2 = $20	2 × $10 = $20	$40
Gemini 4 Argon (later price)	10 × $4 = $40	2 × $20 = $40	$80
GPT-6 Astra	10 × $10 = $100	2 × $50 = $100	$200
GPT-6.1 Sol	$20	$20	$40
Claude Fable 5.1	$100	$100	$200
Claude Opus 5.5	$40	$40	$80
Claude Sonnet 5.5	$20	$20	$40

Two things stand out:

1. The $2 tier isn't unique to Google. GPT-6.1 Sol and Claude Sonnet 5.5 cost the same $2 / $10, and you can use both today.
2. Argon's price is introductory. At the announced later price of $4 / $20, it costs the same as Claude Opus 5.5.

What each company says its model is for

Gemini 4 Argon. Google positions it for long, complex work: coding, legal and finance, and cybersecurity defense. Output goes up to 1M tokens (from 64K). Google reports DeepSWE v1.1 77.9% (a record), No. 1 on AutomationBench (51.3%), LVBench 91.7% and CWE-bench 68% (tied first).

GPT-6 Astra. OpenAI's pitch: "Anything you can do on a computer, Astra can do for you." OpenAI says it's state of the art on FrontierMath Tier 4, ARC-AGI 3 and TerminalBench 4.0. Its cheaper sibling GPT-6.1 Sol matches Astra on DeepSWE, according to OpenAI.

Claude. Fable 5.1 is Anthropic's most capable generally available model, built for long-running work. Opus 5.5 "performs at the level of Fable 5.1 on most work", according to Anthropic, and is 40% cheaper to run than Opus 5 and over 30% faster.

Why the benchmarks don't settle it

Every number above is the company's own result on its own setup. Different harnesses, prompts and tool access can move a score a lot, so a Google number and an OpenAI number for different benchmarks can't be ranked against each other. Treat them as each vendor's claim about where its model is strong, not as a leaderboard.

If you need a real answer for your use case, run your own eval: 20 to 50 tasks from your actual product, scored the same way on each model.

Which one should you build on today?

• You need it in production this week: Argon isn't an option yet. Compare GPT-6.1 Sol and Claude Sonnet 5.5 at $2 / $10, or Claude Opus 5.5 at $4 / $20 if you need more capability.
• You need the top tier now: GPT-6 Astra or Claude Fable 5.1, both $10 / $50.
• You're planning for later and cost matters most: watch for Argon's paid API. Budget at the $4 / $20 price, not the introductory one.

Sources

• Google: Gemini 4 Argon
• OpenAI: GPT-6 Astra · GPT-6.1 Sol
• Anthropic: Claude Fable · Claude Opus 5.5 · Pricing

I make clear tech and AI explainers on RainyTech. Which model are you building on right now? Tell me in the comments.

Comments

[Paul Irolla]

The headline gap is a list price. On an agent, most input is the same prefix on every call, so the cache hit rate sets the real gap. Compare the cached rate per model, then multiply by your call count.

[RainyTech]

Fair point, Paul. My tables use list prices only. For agents, where most of each call is the same cached prefix, the cached input rate × your call count is what actually decides the bill. Thanks for adding that.

[Harun - solo dev]

rainytech, this is a brilliantly clear breakdown of the llm pricing and availability landscape! 🐯

your point about "run your own eval: 20 to 50 tasks from your actual product" is the absolute golden rule of llm engineering. vendor benchmarks are marketing; real-world performance on your specific edge cases is what actually matters.

this perfectly mirrors the model routing logic we built into koda. we don't fire up a heavy, expensive model for a simple syntax check. we route to a fast, cheap model (like a 20b) for quick tasks, and reserve the heavy compute (120b) only for complex architectural debugging.

since you've been digging into these apis, i'm curious: have you noticed any significant differences in rate-limiting behavior or context-window handling between gpt-6.1 sol and claude sonnet 5.5 at that $2/$10 tier? for indie devs, those operational limits often matter more than the raw token price.

fantastic, highly practical analysis. thanks for keeping the community grounded in reality! 🛡️📊

[RainyTech]

Thanks Harun, and thanks for flagging that phishing comment 🙏 I've hidden it.

Good question. I haven't tested rate limits or long-context behavior for GPT-6.1 Sol vs Claude Sonnet 5.5 myself. This piece only compares list prices and what each company publishes. Both set rate limits by account tier, so check each provider's rate-limit docs for your plan. A hands-on test of exactly that would make a good follow-up.

[Harun - solo dev]

rainytech, you're very welcome! glad i could help keep the feed clean. 🛡️

that makes total sense regarding the rate limits. i'll definitely keep an eye on the provider docs and maybe run a small load test on my end to see how gpt-6.1 sol handles sustained, 3g-friendly payloads compared to sonnet.

thanks again for the top-tier, no-fluff breakdown!

[Rahul R]

At $10/$50, models like GPT-6 Astra and Claude Fable 5.1 are 5x more expensive than the $2/$10 tier (Sol/Sonnet 5.5). For those testing Astra's autonomous computer use capabilities or Fable 5.1's ability to run unattended for days, is that top tier actually delivering 5x the business value in your production environment?

I'm new to dev.to! Any feedback or thoughts on my posts would be greatly appreciated.

[RainyTech]

Welcome to dev.to, Rahul! This piece was a pricing comparison, not a hands-on test, so I can't say whether the $10/$50 tier delivers 5x. My approach: start at $2/$10 and only move a task up when your own eval shows the cheaper model failing on it.

[Paul Irolla]

@rainytechlab Right, and the cache hit rate is the part that moves. One change in the prefix mid-session, like a timestamp or a reordered tool list, makes every turn after it pay full price.

[RainyTech]

Good catch, and an easy one to miss. Keep everything that changes per call (timestamps, request IDs, the newest user message) at the end, and keep the tool list in a fixed order, so the cached prefix stays identical from turn to turn.