Compare models
Put up to 4 models beside each other — token prices, context windows, capabilities and provider, from the same catalogue the model pages read.
| Attribute | GPT-6 Luna Progpt-6-luna-pro | S2.1 Pros2.1-pro |
|---|---|---|
| Pricing | ||
| Input | $0.10 / 1M | $0 / 1M |
| Output | $0.50 / 1M | $0 / 1M |
| Cache Write (5m) | $0.10 / 1M | Not applicable |
| Cache Write (1h) | $0.10 / 1M | Not applicable |
| Cache Read | $0.10 / 1M | Not applicable |
| Web Search | $0 / 1M | $0 / 1M |
| Context | ||
| Max context | 1.1M | N/A |
| Max output | N/A | N/A |
| Capabilities | ||
| Vision | Yes | No |
| Function Calling | Yes | No |
| JSON Mode | Yes | No |
| Streaming | Yes | No |
| Catalogue | ||
| Provider | OpenAI | Fish Audio |
| Category | chat | voice |
| Charge type | Pay As You Go | Pay As You Go |
| Released | — | 2026-07-29 |
| Description | ||
| Summary | GPT-6 Luna Pro uses the same underlying model as GPT-6 Luna, but runs with reasoning.mode set to pro for higher-quality responses on complex tasks. It combines Luna's speed and cost efficiency with deeper reasoning and more reliable multi-step execution, making it well suited for advanced coding, computer use, and agentic workflows where higher solution quality is needed without moving to a larger GPT-6 tier. | Fish Audio S2.1 Pro text-to-speech. Billed per UTF-8 byte of input text. |