GPT-6 Astra vs. Claude Fable 5.1: API Cost Comparison
On this API, GPT-6 Astra costs $3.5 / $17.5 per 1M tokens (in/out) and Claude Fable 5.1 costs $5 / $25. GPT-6 Astra is the cheaper option, and both run on the same key — switching is a one-line model parameter change.
Per-token pricing
| GPT-6 Astra | Claude Fable 5.1 | |
|---|---|---|
| Vendor | OpenAI | Anthropic |
| Input · per 1M tokens · Official list | $10 | $10 |
| Input · per 1M tokens · Your price | $3.5 | $5 |
| Output · per 1M tokens · Official list | $50 | $50 |
| Output · per 1M tokens · Your price | $17.5 | $25 |
| Discount vs. list | -65% | -50% |
| Context window | 400K tokens | 200K tokens |
| Max output tokens | 128K tokens | 128K tokens |
All prices in USD per 1M tokens.
What a real workload costs
Same request stream priced on both models — 10M input + 2M output tokens per month, a typical coding-agent load:
GPT-6 Astra
- At official list
- $200 per month
- On this API
- $70 per month
Claude Fable 5.1
- At official list
- $200 per month
- On this API
- $100 per month
Switching between them
Both models answer on the same endpoint. Keep your base URL and key; change only the model parameter to reroute a request:
curl https://kktt.net/v1/chat/completions \
-H "Authorization: Bearer $API_KEY" \
-d '{"model": "gpt-6-astra", "messages": [...]}'curl https://kktt.net/v1/chat/completions \
-H "Authorization: Bearer $API_KEY" \
-d '{"model": "claude-fable-5-1", "messages": [...]}'FAQ
Which is cheaper, GPT-6 Astra or Claude Fable 5.1?
On this API, GPT-6 Astra is cheaper: $3.5 in / $17.5 out per 1M tokens, versus $5 in / $25 out for Claude Fable 5.1.
Can I use GPT-6 Astra and Claude Fable 5.1 with the same API key?
Yes. Both are callable with one key on the same base URL — switching between them is a one-line change of the model parameter, which makes A/B testing or fallback routing trivial.
Do GPT-6 Astra and Claude Fable 5.1 differ in context window?
GPT-6 Astra supports 400K of context with 128K max output; Claude Fable 5.1 supports 200K with 128K max output.