A side-by-side comparison of Claude Sonnet 5.5 and Kimi K3.1 Pro: input/output pricing, capabilities and available endpoints, served live from 国际云宝子（Ai）. Both are reachable with the same API key.
| Item | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Input (per 1M tokens) | $1.8 | $1.1 |
| Output (per 1M tokens) | $9 | $5.5 |
| Cache read explicit (per 1M tokens) | $0.18 | $0.11 |
| Cache write 5m (per 1M tokens) | $2.25 | $1.1 |
| Item | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Context window | 1,000,000 | 1,048,576 |
| Max output | 128,000 | 1,048,576 |
| Item | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| function_calling | Yes | Yes |
| input_video | — | Yes |
| prompt_caching | Yes | Yes |
| structured_output | — | Yes |
| thinking | — | Yes |
| vision | Yes | Yes |
On input, Kimi K3.1 Pro is cheaper ($1.8 vs $1.1 per 1M tokens). On output, Kimi K3.1 Pro is cheaper ($9 vs $5.5 per 1M tokens). All prices are per million tokens in USD.
Kimi K3.1 Pro does — Claude Sonnet 5.5 accepts 1,000,000 input tokens and Kimi K3.1 Pro accepts 1,048,576.
both support function_calling, prompt_caching, vision; only Kimi K3.1 Pro supports input_video, structured_output, thinking.
Yes. Both are available on 国际云宝子（Ai） through one API key and the same OpenAI-compatible endpoint — switching means changing the model field from "claude-sonnet-5-5" to "kimi-k3.1-pro", nothing else.
Both are available on 国际云宝子（Ai） under one API key — switching between them means changing the model field and nothing else, so you can use each where it fits rather than picking one.