Compare models
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| Attribute | S1s1 | GPT-6 Astragpt-6-astra | GPT-6 Solgpt-6-sol | Universal-3.5 Prouniversal-3-5-pro |
|---|---|---|---|---|
| Pricing | ||||
| Input | $0 / 1M | $10.00 / 1M | $2.00 / 1M | $0 / 1M |
| Output | $0 / 1M | $50.00 / 1M | $10.00 / 1M | $0 / 1M |
| Cache Write (5m) | Not applicable | $10.00 / 1M | $2.00 / 1M | Not applicable |
| Cache Write (1h) | Not applicable | $10.00 / 1M | $2.00 / 1M | Not applicable |
| Cache Read | Not applicable | $10.00 / 1M | $2.00 / 1M | Not applicable |
| Web Search | $0 / 1M | $0 / 1M | $0 / 1M | $0 / 1M |
| Context | ||||
| Max context | N/A | 1M | 1.1M | N/A |
| Max output | N/A | N/A | N/A | N/A |
| Capabilities | ||||
| Vision | No | Yes | Yes | No |
| Function Calling | No | Yes | Yes | No |
| JSON Mode | No | Yes | Yes | No |
| Streaming | No | Yes | Yes | No |
| Catalogue | ||||
| Provider | Fish Audio | OpenAI | OpenAI | AssemblyAI |
| Category | voice | chat | chat | voice |
| Charge type | Pay As You Go | Pay As You Go | Pay As You Go | Pay As You Go |
| Released | 2026-07-29 | — | — | 2026-09-22 |
| Description | ||||
| Summary | Fish Audio S1 text-to-speech. Billed per UTF-8 byte of input text. | 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. | GPT-6 Sol is OpenAI's cost-efficient high-end model in the GPT-6 series, positioned between the flagship GPT-6 Astra and the fast GPT-6 Luna tier. It is designed for professional knowledge work, agentic coding, business workflow automation, and computer-use tasks, with particular strength in long-horizon software engineering across real-world codebases. GPT-6 Sol approaches Astra-level factual reliability at a significantly lower cost, while sharing its clear and concise communication style. This balance of capability, reliability, and efficiency makes it well suited for production agents, complex engineering workflows, and scalable professional applications | AssemblyAI Universal-3.5 Pro speech-to-text. Billed per second of audio. |