LLM Gateway / Compare / Claude Opus 5.5 vs GPT-6 Astra
Anthropic vs OpenAI

Claude Opus 5.5 vs GPT-6 Astra

Claude Opus 5.5 costs less: $20.00 less per 1M input tokens and $68.75 less per 1M output tokens. Both take images, call tools and reason before answering. Only GPT-6 Astra can return JSON. Claude Opus 5.5 reads up to 1M tokens at once, GPT-6 Astra 1.05M. Both run on one withConflux key.

Try both on one keyCheck my bill free
Pick Claude Opus 5.5 if
  • output is a big part of your bill (chat, agents): $25.00 vs $93.75 per 1M
  • your prompts are long (documents, big context): $5.00 vs $25.00 per 1M in
  • your prompts and tools are already tuned for Claude
Pick GPT-6 Astra if
  • you need JSON mode
  • you want the larger context (1.05M tokens)
  • your prompts and tools are already tuned for GPT
Side by side

The numbers

Claude Opus 5.5GPT-6 Astra
Input, per 1M tokens$5.00$25.00
Output, per 1M tokens$25.00$93.75
Context1M tokens1.05M tokens
Can usevision, tools, reasoningvision, tools, JSON, reasoning
Typical answer, our gatewayNot measured yetNot measured yet
First tokenNot measured yetNot measured yet

Green = better on that row. Speed for every model: API speed.

What a month costs

Three real workloads

At your price on withConflux. Change the numbers in the calculator below to match your traffic.

WorkloadClaude Opus 5.5GPT-6 Astra
Support chatbot
30,000 messages a month, 1,500 tokens in and 300 out each
$450.00$1968.75
Coding agent
2,000 tasks a month, 40,000 tokens in and 4,000 out each
$600.00$2750.00
Document summaries
10,000 documents a month, 8,000 tokens in and 600 out each
$550.00$2562.50

What a month costs

30,000 messages, about 1,500 tokens in and 300 out each. Change the numbers to match yours.
Claude Opus 5.5
$450.00
GPT-6 Astra
$1968.75
At your price on Managed: the provider’s price plus a small margin. With your own keys you pay the provider directly, plus €19 a month for the gateway.
Switching

One word in your code

from openai import OpenAI
client = OpenAI(base_url="https://withconflux.com/v1", api_key="cflx_live_...")
client.chat.completions.create(model="gpt-6-astra", messages=[...])   # or "claude-opus-5-5"

Run both and see for yourself

Sign up free and call Claude Opus 5.5 and GPT-6 Astra with the same key. Each call shows its cost per key.

Questions

Claude Opus 5.5 vs GPT-6 Astra, answered

Which one is cheaper?

Claude Opus 5.5 is cheaper for both input and output.

Can I switch without changing my code?

On withConflux, yes: both are behind the same OpenAI-compatible endpoint. You change the model name.

Do I need an Anthropic and an OpenAI account?

No. One withConflux key calls both. With your own keys (BYOK) you can use your accounts instead, for €19 a month.

How fresh are these numbers?

Prices are read from our live model list. Speed is recalculated every hour from the last 7 days. The date is on the page.

Keep comparing

Related

Claude Opus 5.5 guideGPT-6 Astra guideAll pairsAPI speed
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Claude Opus 5.5 vs GPT-6 Astra: price, speed and which to pick — withConflux