GLM 5.3 Flash

GLM 5.3 Flash is the efficient tier of the GLM-5.3 generation from Zhipu (Z.ai), tuned for coding and long-horizon agent tasks rather than raw scale. It is natively multimodal on the way in, accepting text, images and video, and it returns text. A hybrid sparse and linear attention architecture is what lets it hold accurate behaviour across the full 1M-token context while keeping compute overhead down, and it ships with function calling, structured outputs and reasoning. One practical note for builders: reasoning is enabled by default and those tokens bill as output and are spent before the prose, so size max_tokens for the thinking as well as the answer. Reach for it when you want long-context, tool-calling, vision-capable work at the lowest rate in the GLM line.

Quick start

Use any OpenAI-compatible client. Just change base_url and your key.

from openai import OpenAI

client = OpenAI(
    api_key="tl-xxxxxxxxxxxxxxxxxxxxxxxx",
    base_url="https://api.thalam.ai/v1",
)

response = client.chat.completions.create(
    model="zhipu/glm-5.3-flash",
    messages=[
        {"role": "user", "content": "Hello from Thalam!"}
    ],
)

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