Model comparison
GLM-5.1 vs o1
GLM-5.1 (Z.ai) and o1 (OpenAI) 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.
What a month costs on each
| Workload | GLM-5.1 | o1 |
|---|---|---|
| Chatbot month (15M in, 4M out) | $29.75 | $465.00 |
| RAG month (40M in, 3M out) | $52.50 | $780.00 |
| Coding month (60M in, 10M out) | $98.00 | $1500.00 |
On a typical 75/25 input-output mix, GLM-5.1 costs less (about 94% less than o1). GLM-5.1 takes the longer prompt at 200K 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-5.1", "messages": [{"role": "user", "content": "Hello"}]}'
# the other one: change the model string
-d '{"model": "openai/o1", ...}'Common questions
Which is cheaper, GLM-5.1 or o1?
GLM-5.1 is cheaper on a typical mix of 75% input and 25% output tokens, by about 94%. Through Rapid Router both are billed at the provider list price per million tokens.
Which has the larger context window?
GLM-5.1, at 200K tokens. o1 offers 200K tokens.
Can I switch between GLM-5.1 and o1 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-5.1 or openai/o1).
How do I pay for GLM-5.1 or o1?
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 GPT: OpenAI API pricing