Gemini 3.5 Flash vs GPT-5.6 Luna
Gemini 3.5 Flash (Google) vs GPT-5.6 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-5.6 Luna is the cheaper option.
Specs side by side
| Spec | Gemini 3.5 Flash | GPT-5.6 Luna |
|---|---|---|
| Provider | OpenAI | |
| Type | Text | Text |
| Context window | 1M | 1M |
| Max output | 64K | 128K |
| Input price | $1.50 / 1M | $0.20 / 1M |
| Output price | $9.00 / 1M | $1.20 / 1M |
| Speed | Fast | Fast |
| Arabic support | Strong | Strong |
Which should you choose?
- Google's fast Gemini 3.5 Flash. Near-frontier quality for agents and coding at high speed and low cost, with very long context
- Lower cost, about 7.5× cheaper ($0.20 / 1M)
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 Gemini 3.5 Flash and GPT-5.6 Luna?
GPT-5.6 Luna costs less ($0.20 / 1M vs $1.50 / 1M). Both are available on thalam behind one OpenAI-compatible API.
Is Gemini 3.5 Flash or GPT-5.6 Luna cheaper?
GPT-5.6 Luna is cheaper on input ($0.20 / 1M vs $1.50 / 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 Gemini 3.5 Flash and GPT-5.6 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.