GLM-5.3 Flash - MixRoute API

GLM-5.3 Flash is Z.ai’s first natively multimodal GLM-5 model, built for efficient coding, agentic work, and visual understanding at lower inference cost. Call glm-5.3-flash through MixRoute using the endpoint below.

Key capabilities

Native multimodality - Understands text, images, video, and files
1M context window - Supports long-context professional workflows
Efficient MoE - 320B total parameters with 18B active
Agentic workflows - Supports coding, tools, and multi-step execution

Quick example

cURL
Python

curl "https://api.mixroute.ai/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "glm-5.3-flash",
  "messages": [
    {"role": "user", "content": "Review this deployment plan and identify the highest-risk rollback gap."}
  ],
  "max_tokens": 256,
  "reasoning_effort": "high"
}'

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.mixroute.ai/v1")

response = client.chat.completions.create(
    model="glm-5.3-flash",
    messages=[{"role": "user", "content": "Review this deployment plan and identify the highest-risk rollback gap."}],
    max_tokens=256,
    reasoning_effort="high",
)

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

Parameters

Parameter	Type	Required	Description
`model`	string	Yes	Model ID. Must be `glm-5.3-flash`.
`messages`	array	Yes	Conversation messages with role and content.
`max_tokens`	integer	No	Maximum generated tokens.
`stream`	boolean	No	Enable SSE streaming.
`reasoning_effort`	string	No	Reasoning effort when supported. Supported values: `low`, `high`, and `max`.
`tools`	array	No	OpenAI-compatible tool definitions.

Vendor reference

Z.ai GLM-5.3 Flash announcement