What is Z.ai: GLM 5.1's context window?

Z.ai: GLM 5.1 supports a context window of 200,000 tokens, allowing you to process large documents and maintain long conversations.

How to use Z.ai: GLM 5.1 API via Ofox?

Simply set your base URL to https://api.ofox.io/v1 and use your Ofox API key. The API is OpenAI-compatible — just change the base URL and API key in your existing code.

Z.ai: GLM 5.1

Name: Z.ai: GLM 5.1
Brand: z-ai
Price: 1.4 USD
Availability: InStock
Rating: 5 (1 reviews)

Chat

z-ai/glm-5.1

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Context Window

200K

Max Output Tokens

128K

Released

2026-03-27

Capabilities

Function CallingReasoningPrompt CachingWeb Search

Available Providers

ZhipuAliyun

Supported Protocols

openaianthropic

Playground

Open in OfoxChat

Chat with this model right here. Conversations live only in this page and are never stored.

Conversations are not saved — leaving or refreshing this page clears them.

Providers

Aliyun

Input Tokens

$1.4/M

Output Tokens

$4.4/M

Cache Read

$0.26/M

Cache Write

$1.5/M

Web Search

$0.01/R

Protocols

openai/v1/chat/completions

anthropic

Zhipu

Input Tokens

$1.4/M

Output Tokens

$4.4/M

Cache Read

$0.26/M

Web Search

$0.01/R

Protocols

openai/v1/chat/completions

anthropic

Code Examples

from openai import OpenAI

client = OpenAI(
    base_url="https://api.ofox.io/v1",
    api_key="YOUR_OFOX_API_KEY",
)

response = client.chat.completions.create(
    model="z-ai/glm-5.1",
    messages=[
        {"role": "user", "content": "Hello!"}
    ],
)

print(response.choices[0].message.content)

Uptime & Status

Benchmarks

LMArena ↗Evaluated as glm-5.1

Z.ai: GLM 5.1 scores 1472 in the Overall category of the LMArena text leaderboard (style control), ranking #25 of 374 models based on 27,322 human preference votes (updated 2026-07-12).

Benchmark scores for glm-5.1 on LMArena
Category	Arena Score	95% CI	Rank	Votes
Overall	1472	1467–1477	#25 of 374	27,322
Hard Prompts	1494	1488–1500	#22 of 374	18,029
Coding	1522	1514–1529	#17 of 369	7,638
Math	1479	1463–1495	#18 of 362	1,432
Creative Writing	1454	1445–1464	#19 of 372	4,644
Instruction Following	1465	1458–1472	#21 of 374	9,253
Chinese	1518	1502–1534	#18 of 344	1,561

Source: LMArena · CC BY 4.0 · Updated 2026-07-12 · Methodology ↗ · Ranks compare models within each category of the LMArena text leaderboard (style control). Scores come from third-party human preference evaluations, not from OFOX.