OpenLuxClaude Opus 5 vs Claude Fable 5.1
Claude Opus 5 and Claude Fable 5.1 both run on OpenLux behind one OpenAI-compatible endpoint. Claude Opus 5 is metered at $0.4412 per 1M tokens (-91% vs official rates); Claude Fable 5.1 at $1.765 per 1M tokens (-82% vs official rates). Claude Opus 5 is the lower-cost option per unit — about 75% cheaper on the same OpenLux endpoint. This page compares their rates, strengths and best-fit workloads so you can route each request to the right model.
The short version
In practice the two models are complements, not substitutes: Claude Opus 5 suits workloads that need agents and apps that call tools or functions, production chat and assistant workloads. Claude Fable 5.1 is the better fit when you need agents and apps that call tools or functions, prompts that include images, charts or screenshots. Both are called with the same OpenLux key, so switching between them is a one-field change to the model name.
Choose Claude Opus 5 when
- You need agents and apps that call tools or functions.
- You need production chat and assistant workloads.
- Unit cost is the deciding factor for this workload.
Choose Claude Fable 5.1 when
- You need agents and apps that call tools or functions.
- You need prompts that include images, charts or screenshots.
Rates on OpenLux
| Model | Provider | Rate | Discount |
|---|---|---|---|
| Claude Opus 5 | Anthropic | $0.4412 per 1M tokens | -91% |
| Claude Fable 5.1 | Anthropic | $1.765 per 1M tokens | -82% |
Rates follow official provider pricing and are billed in USD. See the full catalogue and pricing plans for credit allowances.
One snippet, two models
Claude Opus 5 and Claude Fable 5.1 share the same OpenAI-compatible request shape. Run the same code against both and compare the answers on your own workload.
from openai import OpenAI
client = OpenAI(
api_key="sk-openlux-...",
base_url="https://openlux.lol/v1",
)
for model in ["claude-opus-5", "claude-fable-5-1"]:
resp = client.chat.completions.create(
model=model,
messages=[{"role": "user", "content": "Summarise this release note for me."}],
)
print(model, "->", resp.choices[0].message.content)Any OpenAI SDK works the same way — see the docs for streaming, tools and error codes.
Claude Opus 5 vs Claude Fable 5.1 questions
How much do Claude Opus 5 and Claude Fable 5.1 cost on OpenLux?
Claude Opus 5 is metered pay as you go at $0.4412 per 1M tokens, a -91% discount on official list pricing. Claude Fable 5.1 is metered at $1.765 per 1M tokens, a -82% discount. There is no subscription requirement: usage is billed in USD and every request is visible in the console.
Can I call Claude Opus 5 and Claude Fable 5.1 with the same API key?
Yes. Both models sit behind the same OpenAI-compatible endpoint at https://openlux.lol/v1. Keep the same key and change only the "model" field to switch between claude-opus-5 and claude-fable-5-1 — request and response shapes stay identical.
Which is cheaper, Claude Opus 5 or Claude Fable 5.1?
Claude Opus 5 costs less per unit: $0.4412 per 1M tokens versus $1.765 per 1M tokens, about 75% lower for the same volume. Over a month of production traffic the difference compounds, and the console shows cost per request in real time.
When should I pick Claude Opus 5 over Claude Fable 5.1?
In practice the two models are complements, not substitutes: Claude Opus 5 suits workloads that need agents and apps that call tools or functions, production chat and assistant workloads. Claude Fable 5.1 is the better fit when you need agents and apps that call tools or functions, prompts that include images, charts or screenshots. Both are called with the same OpenLux key, so switching between them is a one-field change to the model name.
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Route every request to the right model
OpenLux keeps Claude Opus 5, Claude Fable 5.1 and every other model behind one key, one endpoint and one bill. Start with free trial credit and switch models without touching your code.