GLM-4.5-Air vs Kimi K3
GLM-4.5-Air (Z.ai) and Kimi K3 (Moonshot) 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.
| GLM-4.5-Air | Kimi K3 | |
|---|---|---|
| Input price per 1M | $0.030 | $0.304 |
| Output price per 1M | $0.140 | $11.94 |
| Context window | 131K tokens | 1M tokens |
| Max output | 98K tokens | 1M tokens |
| Input types | text | text, image, video |
| Capabilities | tools, reasoning | tools, JSON, vision, reasoning |
| Author | Z.ai | Moonshot |
| LMArena Overall | 1384 | 1475 |
| LMArena Coding | 1397 | 1507 |
| LMArena Math | 1396 | 1494 |
| LMArena Creative writing | 1343 | 1456 |
| LMArena Instruction following | 1354 | 1483 |
| LMArena Hard prompts | 1379 | 1494 |
| LMArena Web dev | — | 1655 |
| GPQA Diamond | — | 93.1% |
| OTIS Mock AIME | — | 97.2% |
| SimpleQA Verified | — | 50.6% |
| Humanity's Last Exam | 8.1% | — |
Scores from LMArena and Epoch AI, as published; a blank cell means not measured there.
What a month costs on each
| Workload | GLM-4.5-Air | Kimi K3 |
|---|---|---|
| Chatbot month (15M in, 4M out) | $1.01 | $52.30 |
| RAG month (40M in, 3M out) | $1.62 | $47.97 |
| Coding month (60M in, 10M out) | $3.20 | $137.60 |
On a typical 75/25 input-output mix, GLM-4.5-Air costs less (about 98% 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": "z-ai/glm-4.5-air", "messages": [{"role": "user", "content": "Hello"}]}'
# the other one: change the model string
-d '{"model": "moonshotai/kimi-k3", ...}'Common questions
Which is cheaper, GLM-4.5-Air or Kimi K3?
GLM-4.5-Air is cheaper on a typical mix of 75% input and 25% output tokens, by about 98%. 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. GLM-4.5-Air offers 131K tokens.
Can I switch between GLM-4.5-Air and Kimi K3 without changing code?
Yes. Both are callable at https://rapidrouter.ai/api/v1 with the same OpenAI-compatible request; only the model string changes (z-ai/glm-4.5-air or moonshotai/kimi-k3).
How do I pay for GLM-4.5-Air or Kimi K3?
Top up a Rapid Router balance by card in US dollars, and both models debit that balance per request.
More GLM models: Z.ai API pricing · More Kimi: Moonshot API pricing