Z.ai: GLM-5.1
GLM-5.1 is a reasoning model from Z.ai released on Mar 27, 2026. It reads text and writes text, with a 200K token context window and up to 131K tokens per reply.
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It costs $1.40 per million input tokens and $4.40 per million output tokens. Cached input bills at $0.26, 81% less than fresh input.
It supports tool calling, structured JSON output and prompt caching, and its weights are open, so you can host it yourself.
43 providers serve it, including Baseten, Novita AI and Friendli. The lowest input price is $0.45 per million tokens at CrofAI.
- Modalities
- In / out price
- $1.40 / $4.40 per 1M
- Context
- 200K
- Max output
- 131K
- Released
- Mar 27, 2026
- Knowledge cutoff
- n/a
- Tool calling
- Structured output
- Reasoning
- Prompt caching
- Open weights
- Free to use
GLM-5.1 pricing
USD, as listed on Oct 15, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.
| Input | $1.40 / 1M tokens | |
|---|---|---|
| Output | $4.40 / 1M tokens | |
| Cached input (read) | $0.26 / 1M tokens | 81% off input |
| Cache write | $0 / 1M tokens |
GLM-5.1 providers
43 providers serve it, including Baseten, Novita AI and Friendli. The lowest input price is $0.45 per million tokens at CrofAI. Each host sets its own price and limits, so the cheapest one is not always the one with the longest context.
| Provider | Input /M | Output /M | Cache read /M | Context | Max output |
|---|---|---|---|---|---|
| Zhipu AI First party | $1.40 | $4.40 | $0.26 | 200K | 131K |
| Baseten | $1.30 | $4.30 | $0.26 | 203K | 203K |
| Novita AI | $1.38 | $4.40 | $0.26 | 205K | 131K |
| Friendli | $1.40 | $4.40 | $0.26 | 203K | 131K |
| Vercel AI Gateway | $1.40 | $4.40 | $0.26 | 203K | 64K |
| CrofAI | $0.45 | $2.15 | $0.08 | 203K | 203K |
| NanoGPT | $0.70 | $2.50 | $0.18 | 200K | 131K |
| Alibaba (China) | $0.825 | $3.30 | $0.17 | 203K | 128K |
| EmpirioLabs AI | $0.825 | $3.30 | $0.165 | 202K | 128K |
| EBCloud | $0.8571 | $3.43 | – | 200K | 131K |
| ZenMux | $0.8781 | $3.51 | $0.1903 | 200K | 128K |
| DevPass (LLM Gateway) | $0.931 | $2.93 | $0.173 | 205K | 131K |
Showing 12 of 43 providers: the lab first, then the major clouds, then the cheapest resellers.
What GLM-5.1 costs per month
Pick a workload close to yours or type your own volumes.
Supported request parameters
What you can set when you call GLM-5.1 through an OpenAI compatible API.
- Tools
tools - Structured outputs
structured_outputs - Reasoning
reasoning - Temperature
temperature
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GLM-5.1 questions
How much does the GLM-5.1 API cost?
$1.40 per million input tokens and $4.40 per million output tokens, with cached input at $0.26. The estimator on this page turns that into a monthly bill for your own workload.
What is the context window of GLM-5.1?
200,000 tokens of input, and it can write up to 131,072 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.
Which providers serve GLM-5.1?
43 providers serve it, including Baseten, Novita AI and Friendli. The lowest input price is $0.45 per million tokens at CrofAI. Prices differ by host, so the Providers table on this page lists each one with its input and output price.
Does GLM-5.1 support tool calling?
Yes. It accepts tool definitions and can return JSON that matches a schema, which is what an agent needs to call your APIs.
Is GLM-5.1 open source?
Its weights are published, so you can run it on your own hardware or a cloud of your choice. Read the license before commercial use.
When was GLM-5.1 released?
Mar 27, 2026.
Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 15, 2026. The summary is written from these facts.
Building on GLM-5.1?
I test your real tasks on it and the two closest alternatives, then ship the agent on whichever wins on cost and accuracy.
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