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.
4 is the maximum. Remove one to add another.
| Attribute | S2 Pros2-pro | GPT-6 Astragpt-6-astra | GPT-6 Solgpt-6-sol | Claude Sonnet 5.5claude-sonnet-5.5 |
|---|---|---|---|---|
| Pricing | ||||
| Input | $0 / 1M | $10.00 / 1M | $2.00 / 1M | $2.00 / 1M |
| Output | $0 / 1M | $50.00 / 1M | $10.00 / 1M | $10.00 / 1M |
| Cache Write (5m) | Not applicable | $10.00 / 1M | $2.00 / 1M | $2.50 / 1M |
| Cache Write (1h) | Not applicable | $10.00 / 1M | $2.00 / 1M | $4.00 / 1M |
| Cache Read | Not applicable | $10.00 / 1M | $2.00 / 1M | $0.20 / 1M |
| Web Search | $0 / 1M | $0 / 1M | $0 / 1M | $0 / 1M |
| Context | ||||
| Max context | N/A | 1M | 1.1M | 1M |
| Max output | N/A | N/A | N/A | N/A |
| Capabilities | ||||
| Vision | No | Yes | Yes | Yes |
| Function Calling | No | Yes | Yes | Yes |
| JSON Mode | No | Yes | Yes | Yes |
| Streaming | No | Yes | Yes | Yes |
| Catalogue | ||||
| Provider | Fish Audio | OpenAI | OpenAI | Anthropic |
| Category | voice | chat | chat | chat |
| Charge type | Pay As You Go | Pay As You Go | Pay As You Go | Pay As You Go |
| Released | 2026-07-29 | — | — | — |
| Description | ||||
| Summary | Fish Audio S2 Pro 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 | Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, serving as a direct upgrade to Sonnet 5. It excels at feature development, bug fixing, and creating polished documents, presentations, and spreadsheets, while offering clearer writing and communication than its predecessor. |