Z.ai: GLM 4.5 Air (free)✓ Catalog verified
GLM-4.5-Air is the lightweight variant of our latest flagship model family, also purpose-built for agent-centric applications. Like GLM-4.5, it adopts the Mixture-of-Experts (MoE) architecture but with a more compact parameter size. GLM-4.5-Air also supports hybrid inference modes, offering a "thinking mode" for advanced reasoning and tool use, and a "non-thinking mode" for real-time interaction. Users can control the reasoning behaviour with the `reasoning` `enabled` boolean. Learn more in our docs
Overview
GLM-4.5-Air is the lightweight variant of our latest flagship model family, also purpose-built for agent-centric applications. Like GLM-4.5, it adopts the Mixture-of-Experts (MoE) architecture but with a more compact parameter size. GLM-4.5-Air also supports hybrid inference modes, offering a "thinking mode" for advanced reasoning and tool use, and a "non-thinking mode" for real-time interaction. Users can control the reasoning behaviour with the `reasoning` `enabled` boolean. Learn more in our docs
Access: available through the official Z Ai API. Context window: 131K.
Specifications
| API identifier | z-ai/glm-4.5-air:free |
| Provider | Z Ai |
| Model type | Text LLM |
| Context window | 131K catalog |
| Input modalities | text |
| Output modalities | text |
| Released | Jul 25, 2025 |
| Moderated | No |
| Architecture modality | text->text |
API defaults
{
"top_p": null,
"temperature": 0.75,
"frequency_penalty": null
}Pricing
Live pricing components for z-ai/glm-4.5-air:free as published in the catalog.
| Pricing component | Raw unit price | Normalized | Unit |
|---|---|---|---|
| Prompt tokens | $0 | $0.00 / 1M | Per input token |
| Completion tokens | $0 | $0.00 / 1M | Per output token |
| Request fee | N/A | N/A | Per request |
| Image fee | N/A | N/A | Per image unit |
| Web search fee | N/A | N/A | Per search request |
Cost calculator
Estimate monthly spend from your own token volumes.
Estimated Total Cost
$0Calculated from current list pricing in the ModelsAtlas catalog.Capabilities
| Capability | Status | What it means |
|---|---|---|
| Visual Understanding | Not advertised | Image and document analysis support |
| Audio Processing | Not advertised | Speech and voice aligned flows |
| Tool Calling | ✓ Supported | Supports tools / function calling |
| Self-Hosting | Not advertised | Deploy outside managed APIs |
Capability signals
Directional signals derived from model metadata and capability tags — not official benchmark submissions.
Quick start
Call Z.ai: GLM 4.5 Air (free) through an OpenAI-compatible client.
from openai import OpenAI
client = OpenAI(
base_url="https://openrouter.ai/api/v1",
api_key="YOUR_API_KEY"
)
response = client.chat.completions.create(
model="z-ai/glm-4.5-air:free",
messages=[{"role": "user", "content": "Explain quantum physics."}]
)
print(response.choices[0].message.content)Alternatives
Closest models by context window from a different provider.
| Model | Provider | Context | Input /1M | Actions |
|---|---|---|---|---|
| AionLabs: Aion-1.0 | Aion Labs | 131K | $4.00 | View → |
| AionLabs: Aion-1.0-Mini | Aion Labs | 131K | $0.70 | View → |
Sources & attribution
Pricing and metadata are maintained in the ModelsAtlas catalog.
Frequently asked questions
How much does Z.ai: GLM 4.5 Air (free) cost?
$0.00 per 1M input tokens and $0.00 per 1M output tokens on the official Z Ai API.
What is the context window of Z.ai: GLM 4.5 Air (free)?
Z.ai: GLM 4.5 Air (free) supports up to 131K tokens of context.
Does Z.ai: GLM 4.5 Air (free) support tool / function calling?
Yes, Z.ai: GLM 4.5 Air (free) supports tool / function calling — you can register tools and the model will emit structured tool calls.
How do I access Z.ai: GLM 4.5 Air (free)?
Use the official Z Ai API with the model id `z-ai/glm-4.5-air:free`. See the Quick start section above for code examples.