# GLM-5.1

GLM-5.1 costs $1.4 per 1M input tokens and $4.4 per 1M output tokens on LLM API, with a 203K-token context window.

Model ID: `glm-5.1` · Z.ai · Text generation · Released March 27, 2026
Updated: 2026-10-27
Canonical: https://llmapi.ai/models/z-ai-glm-5-1/

- Input: $1.4 per 1M tokens
- Output: $4.4 per 1M tokens
- Cache read: $0.26 per 1M tokens
- Context: 203K tokens
- Max output: 4K tokens

## Pricing

Served by Z.ai, the only provider.

| Price | Amount | Per |
| --- | --- | --- |
| Input | $1.4 | per 1M tokens |
| Output | $4.4 | per 1M tokens |
| Cache read | $0.26 | per 1M tokens |

**Volume pricing.** At higher monthly volume, GLM-5.1 may cost less. Book a call and sales will quote a price for your usage. [Book a call with sales](https://meetings.hubspot.com/julia-andriienko/llmapi) or [Create an account first](https://app.llmapi.ai/signup).

## Features

- Tools: Yes
- Parallel tool calls: No
- Image input: No
- Reasoning: Yes
- Prompt caching: Yes
- Structured outputs: No
- JSON mode: Yes
- Streaming: Yes
- Web search: No

## Call GLM-5.1

### Chat Completions (`POST /v1/chat/completions`)

Set LLMAPI_KEY to your LLM API key.

```python
import os

from openai import OpenAI

client = OpenAI(
    base_url="https://api.llmapi.ai/v1",
    api_key=os.environ["LLMAPI_KEY"],
)

response = client.chat.completions.create(
    model="glm-5.1",
    messages=[{"role": "user", "content": "Hello"}],
)
print(response.choices[0].message.content)
```

Docs: [Chat Completions docs](https://docs.llmapi.ai/api/v1/chat/completions)

## More from Z.ai

- [GLM-5.3](https://llmapi.ai/models/zhipu-glm-5-3/): $0.98 / $3.08 per 1M input / output
- [GLM-5.3-Flash](https://llmapi.ai/models/zhipu-glm-5-3-flash/): $0.118 / $0.472 per 1M input / output
- [GLM 5.2](https://llmapi.ai/models/zhipu-zai-glm-5-2/): $0.84 / $2.64 per 1M input / output

Prices synced 2026-11-03.

Next step: [Get API key](https://app.llmapi.ai/signup)