GPT-5.6 Terra vs GPT-6 Astra
GPT-5.6 Terra (OpenAI) vs GPT-6 Astra (OpenAI), compared on price, context, speed and Arabic support. Both run on thalam through one OpenAI-compatible API, so you can switch between them with a single model id change. At a glance, GPT-5.6 Terra is the cheaper option.
Specs side by side
| Spec | GPT-5.6 Terra | GPT-6 Astra |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Text | Text |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Input price | $2.00 / 1M | $10.00 / 1M |
| Output price | $12.00 / 1M | $50.00 / 1M |
| Speed | Medium | Medium |
| Arabic support | Strong | Strong |
Which should you choose?
- Lower cost, about 5× cheaper ($2.00 / 1M)
- OpenAI's GPT-6 generation. Frontier reasoning with a 1M-token context, image input, and adjustable reasoning effort
One OpenAI-compatible endpoint, one bill. Switch between them with a single model id change, pay per use, credits never expire.
Related comparisons
FAQ
What's the difference between GPT-5.6 Terra and GPT-6 Astra?
GPT-5.6 Terra costs less ($2.00 / 1M vs $10.00 / 1M). Both are available on thalam behind one OpenAI-compatible API.
Is GPT-5.6 Terra or GPT-6 Astra cheaper?
GPT-5.6 Terra is cheaper on input ($2.00 / 1M vs $10.00 / 1M). On thalam you pay per use, so you can route cheap-by-default and fall back to the other only when needed.
Can I use both GPT-5.6 Terra and GPT-6 Astra with one API key?
Yes. thalam is OpenAI-compatible, so both models are reachable through the same endpoint. Switching between them is a one-line model id change, no code rewrite.