Compare models
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| Attribute | GPT-6 Lunagpt-6-luna | GPT-6 Astragpt-6-astra | S1s1 | Grok STT 1.0grok-stt-1.0 |
|---|---|---|---|---|
| Pricing | ||||
| Input | $0.10 / 1M | $10.00 / 1M | $0 / 1M | $0 / 1M |
| Output | $0.50 / 1M | $50.00 / 1M | $0 / 1M | $0 / 1M |
| Cache Write (5m) | $0.10 / 1M | $10.00 / 1M | Not applicable | Not applicable |
| Cache Write (1h) | $0.10 / 1M | $10.00 / 1M | Not applicable | Not applicable |
| Cache Read | $0.10 / 1M | $10.00 / 1M | Not applicable | Not applicable |
| Web Search | $0 / 1M | $0 / 1M | $0 / 1M | $0 / 1M |
| Context | ||||
| Max context | 1.1M | 1M | N/A | N/A |
| Max output | N/A | N/A | N/A | N/A |
| Capabilities | ||||
| Vision | Yes | Yes | No | No |
| Function Calling | Yes | Yes | No | No |
| JSON Mode | Yes | Yes | No | No |
| Streaming | Yes | Yes | No | No |
| Catalogue | ||||
| Provider | OpenAI | OpenAI | Fish Audio | xAI |
| Category | chat | chat | voice | voice |
| Charge type | Pay As You Go | Pay As You Go | Pay As You Go | Pay As You Go |
| Released | — | — | 2026-07-29 | 2026-07-23 |
| Description | ||||
| Summary | GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, optimized for high-volume and latency-sensitive workloads such as chat, classification, and lightweight agentic tasks. It combines low-cost, responsive inference with the GPT-6 family’s improvements in factual reliability and clear, concise communication. At higher reasoning effort, GPT-6 Luna can also handle complex software engineering and computer-use workflows that previously required a Sol-tier model, making it a versatile choice for scalable production applications that need to balance speed, cost, and capability. | GPT-6 Astra is OpenAI's flagship model for demanding end-to-end professional work, designed for advanced analysis, software engineering, deep research, scientific tasks, and document creation. It is particularly strong in long-horizon agentic workflows, including tasks that require sustained reasoning, tool orchestration, and computer and browser use, making it well suited for complex autonomous workflows and production-grade knowledge work. | Fish Audio S1 text-to-speech. Billed per UTF-8 byte of input text. | xAI Grok STT 1.0 speech-to-text. Billed per second of audio. |