GPT-5.6 Sol or Claude Sonnet 5.5?
Choose GPT-5.6 Sol when professional api workflows where token cost and reasoning controls matter is the closer match. Choose Claude Sonnet 5.5 when full-stack software development, automated ui testing and production agent workflows matters more. Test both on the same real tasks before moving a production workflow.
Professional API workflows where token cost and reasoning controls matter
Full-stack software development, automated UI testing and production agent workflows
GPT-5.6 Sol
Professional API workflows where token cost and reasoning controls matter
Official specification ↗Claude Sonnet 5.5
Anthropic's workhorse model with enhanced computer use and sub-second token generation.
Official specification ↗Side-by-side comparison
| Category | GPT-5.6 Sol | Claude Sonnet 5.5 |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Type | Product · Reasoning Model | Model · Balanced reasoning model |
| Pricing summary | API / 1M tokens: $4 input, $0.40 cached input, $20 output; long-context/tool charges extra | $2 input, $0.20 cache read and $10 output per 1M tokens |
| Input price | Product or plan pricing | $2 / 1M tokens |
| Cached input | Not directly comparable | $0.20 / 1M tokens |
| Output price | Product or plan pricing | $10 / 1M tokens |
| Context window | Varies by included model and plan | 500K tokens |
| Maximum output | Varies by included model and surface | 128K tokens |
| Knowledge cutoff | Model-dependent; web access may add current information | August 2026 |
| Reasoning | Varies by selected model or mode | Adaptive thinking with custom effort |
| Relative speed | Varies by model, plan and workload | High throughput |
| Input modalities | See documented product features | Text and image |
| Output modalities | See documented product features | Text |
| Tools and integrations | 1.05M-token context; up to 128K output; Text/image input and text output; Reasoning effort includes none; gpt-5.6 alias routes to Sol | Claude API tool use, desktop computer use, Claude Code |
| API / access | Product surface; see official source for API availability | Claude Messages API |
| Best fit | Professional API workflows where token cost and reasoning controls matter | Full-stack software development, automated UI testing and production agent workflows |
| Company | OpenAI | Anthropic |
| Product category | Product · Reasoning Model | Model · Balanced reasoning model |
| Current pricing note | API / 1M tokens: $4 input, $0.40 cached input, $20 output; long-context/tool charges extra | $2 input, $0.20 cache read and $10 output per 1M tokens |
| Best suited to | Professional API workflows where token cost and reasoning controls matter | Full-stack software development, automated UI testing and production agent workflows |
| Key capabilities | 1.05M-token context; up to 128K output; Text/image input and text output; Reasoning effort includes none; gpt-5.6 alias routes to Sol | Sub-second latency; Enhanced desktop computer use; 500K context; Claude Code default |
| Last verified | 2026-09-07 | 2026-10-15 |
| Official product source | https://developers.openai.com/api/docs/models/gpt-5.6-sol | https://platform.claude.com/docs/en/models/sonnet-5-5/overview |
How we reached this verdict
We looked at the things that affect everyday use: what each product can do, how its plans are structured, where it fits into your existing workflow, and what the provider currently documents. Benchmark results are useful context, but they are not a universal winner score because test settings and tools vary.
Common questions
GPT-5.6 Sol or Claude Sonnet 5.5: which should I choose?
Choose GPT-5.6 Sol for professional api workflows where token cost and reasoning controls matter. Choose Claude Sonnet 5.5 for full-stack software development, automated ui testing and production agent workflows. Validate the decision with your own prompts and total task cost.
Is GPT-5.6 Sol cheaper than Claude Sonnet 5.5?
Pricing units can differ. GPT-5.6 Sol: API / 1M tokens: $4 input, $0.40 cached input, $20 output; long-context/tool charges extra. Claude Sonnet 5.5: $2 input, $0.20 cache read and $10 output per 1M tokens. Check tool charges, plan limits, caching and long-context rules before comparing totals.
Which is better for coding and agent work?
Capability depends on the selected product surface, tools and harness. GPT-5.6 Sol is positioned for professional api workflows where token cost and reasoning controls matter; Claude Sonnet 5.5 is positioned for full-stack software development, automated ui testing and production agent workflows. Run the same repository task on both.
How do their context windows compare?
GPT-5.6 Sol lists Varies by included model and plan; Claude Sonnet 5.5 lists 500K tokens. A larger limit does not by itself guarantee better retrieval or lower cost.
Official sources
Use these provider pages to confirm current features, pricing and availability.
AI tools change quickly. We checked this page on 2026-09-08. Before you subscribe, confirm the latest price, regional availability and usage limits on the provider website.