Model comparison
Kimi K3 vs Mistral Medium 3.1
Kimi K3 (Moonshot) and Mistral Medium 3.1 (Mistral) side by side: what each costs per million tokens through Rapid Router, how much context each takes, what each supports, and where independent benchmarks place them. Same API, same key; switching is a one-string change.
| Kimi K3 | Mistral Medium 3.1 | |
|---|---|---|
| Input price per 1M | $0.304 | $0.400 |
| Output price per 1M | $11.94 | $2.00 |
| Context window | 1M tokens | 262K tokens |
| Max output | 131K tokens | 262K tokens |
| Input types | text, image, video | text, image |
| Capabilities | tools, JSON, vision, reasoning | tools, vision |
| Author | Moonshot | Mistral |
| LMArena Overall | 1475 | 1424 |
| LMArena Coding | 1507 | 1433 |
| LMArena Math | 1494 | 1409 |
| LMArena Creative writing | 1456 | 1391 |
| LMArena Instruction following | 1483 | 1398 |
| LMArena Hard prompts | 1494 | 1426 |
| LMArena Vision | — | 1172 |
| LMArena Web dev | 1655 | — |
| GPQA Diamond | 93.1% | — |
| OTIS Mock AIME | 97.2% | — |
| SimpleQA Verified | 50.6% | — |
Scores from LMArena and Epoch AI, as published; a blank cell means not measured there.
What a month costs on each
| Workload | Kimi K3 | Mistral Medium 3.1 |
|---|---|---|
| Chatbot month (15M in, 4M out) | $52.30 | $14.00 |
| RAG month (40M in, 3M out) | $47.97 | $22.00 |
| Coding month (60M in, 10M out) | $137.60 | $44.00 |
On a typical 75/25 input-output mix, Mistral Medium 3.1 costs less (about 75% less than Kimi K3). Kimi K3 takes the longer prompt at 1M tokens. Try your own numbers in the cost calculator.
Call either one
curl https://rapidrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $RAPIDROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "moonshotai/kimi-k3", "messages": [{"role": "user", "content": "Hello"}]}'
# the other one: change the model string
-d '{"model": "mistralai/mistral-medium-2508", ...}'Common questions
Which is cheaper, Kimi K3 or Mistral Medium 3.1?
Mistral Medium 3.1 is cheaper on a typical mix of 75% input and 25% output tokens, by about 75%. Through Rapid Router both are billed at the provider list price per million tokens.
Which has the larger context window?
Kimi K3, at 1M tokens. Mistral Medium 3.1 offers 262K tokens.
Can I switch between Kimi K3 and Mistral Medium 3.1 without changing code?
Yes. Both are callable at https://rapidrouter.ai/api/v1 with the same OpenAI-compatible request; only the model string changes (moonshotai/kimi-k3 or mistralai/mistral-medium-2508).
How do I pay for Kimi K3 or Mistral Medium 3.1?
Top up a Rapid Router balance by card in US dollars, and both models debit that balance per request.
More Kimi models: Moonshot API pricing · More Mistral: Mistral API pricing