GLM-5.3 Instant

Z.ai’s large model for complex coding and long agent tasks, built on the same base model as GLM-5.2. Answers without a reasoning phase.

Start buildingOpen dashboard

Context window
1M tokens
Accepts
Text
Input per 1M tokens
$1.40
Output per 1M tokens
$4.40

Send your first request

Set LYCEUM_API_KEY to your API key, then run this request. Usage is billed to your account.

Base URL
https://api.lyceum.technology/openai/v1
Model ID
z-ai/glm-5.3-instant
Request fields
model, messages, stream, max_tokens, tools, tool_choice

Documented request fields for this endpoint. See the documentation for model-specific controls and limits.

app.py · Install openai and set LYCEUM_API_KEY

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["LYCEUM_API_KEY"],
    base_url="https://api.lyceum.technology/openai/v1",
)

response = client.chat.completions.create(
    model="z-ai/glm-5.3-instant",
    messages=[{"role": "user", "content": "Hello!"}],
)

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

What it costs

You pay only for the tokens you use.

Token pricing

GLM-5.3 Instant: token prices in US dollars per million tokens
USD per million tokens
Input$1.40
Cached input$0.26
Output$4.40

No base fee. Caching applies only where listed. Check the model's processing region before sending data.

The model in detail

Checked against the sources below. Anything they don't state is left out.

Capabilities

Input and output
Text in, text out
Context window
1M tokens
Reasoning
Disabled
Tool calling
Supported

Architecture and licence

Total parameters
744B
Active parameters
40B
Architecture
Mixture of experts
Released
14 August 2026

Availability

API model ID
z-ai/glm-5.3-instant
Provider
Z.ai
Processing region
EU-hosted
Sources