GPT-5.6 Terra vs GPT-6 Luna
GPT-5.6 Terra (OpenAI) vs GPT-6 Luna (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-6 Luna is the cheaper option and GPT-6 Luna is rated faster.
Specs side by side
| Spec | GPT-5.6 Terra | GPT-6 Luna |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Text | Text |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Input price | $2.00 / 1M | $0.10 / 1M |
| Output price | $12.00 / 1M | $0.50 / 1M |
| Speed | Medium | Fast |
| Arabic support | Strong | Strong |
Which should you choose?
- The balanced tier of OpenAI's GPT-5.6 generation. Same 1M-token context and image input, tuned for everyday production work
- Lower cost, about 20× cheaper ($0.10 / 1M)
- Rated faster (Fast) for latency-sensitive workloads
One OpenAI-compatible endpoint, one bill. Switch between them with a single model id change, pay per use, credits never expire.
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FAQ
What's the difference between GPT-5.6 Terra and GPT-6 Luna?
GPT-6 Luna costs less ($0.10 / 1M vs $2.00 / 1M); GPT-6 Luna is rated faster. Both are available on thalam behind one OpenAI-compatible API.
Is GPT-5.6 Terra or GPT-6 Luna cheaper?
GPT-6 Luna is cheaper on input ($0.10 / 1M vs $2.00 / 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 Luna 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.