GPT-5.6 Luna Pro is the same underlying model as [GPT-5.6 Luna](https://openrouter.ai/openai/gpt-5.6-luna), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://devel…
Model details →OpenAI: GPT-5.6 Luna Pro vs DeepSeek V4 Flash Latest
OpenAI: GPT-5.6 Luna Pro and DeepSeek V4 Flash Latest are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
This model always redirects to the latest model in the DeepSeek V4 Flash family.
Model details →Side-by-side comparison
| Capability | OpenAI: GPT-5.6 Luna Pro | DeepSeek V4 Flash Latest | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 1.1M | 1.0M | 🏆 OpenAI: GPT-5.6 Luna Pro |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $0.10 | $0.09 | 🏆 DeepSeek V4 Flash Latest |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $0.60 | $0.18 | 🏆 DeepSeek V4 Flash Latest |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | — | 🏆 OpenAI: GPT-5.6 Luna Pro |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is OpenAI: GPT-5.6 Luna Pro better than DeepSeek V4 Flash Latest?
OpenAI: GPT-5.6 Luna Pro and DeepSeek V4 Flash Latest are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
What's the price difference between OpenAI: GPT-5.6 Luna Pro and DeepSeek V4 Flash Latest?
Input: $0.10 vs $0.09 per 1M tokens. Output: $0.60 vs $0.18 per 1M tokens.
What context windows do OpenAI: GPT-5.6 Luna Pro and DeepSeek V4 Flash Latest support?
OpenAI: GPT-5.6 Luna Pro supports up to 1.1M tokens. DeepSeek V4 Flash Latest supports up to 1.0M tokens.
Do both OpenAI: GPT-5.6 Luna Pro and DeepSeek V4 Flash Latest support tool calling?
OpenAI: GPT-5.6 Luna Pro: yes. DeepSeek V4 Flash Latest: yes.
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