GLM-5.3-Flash API

Zhipu's cost-efficient, natively multimodal Flash model in the GLM-5 family -- 320B total / 18B active parameters, MIT-licensed, 1M-token context. Formerly the stealth "Ox Alpha" model.
Context
1M tokens
Input
$0.103155 / 1M tokens
Output
$0.34385 / 1M tokens
Released
Aug 26, 2026

How to use GLM-5.3-Flash API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to z-ai/glm-5.3-flash.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "z-ai/glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ]
    },
)
print(r.json())
const r = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "z-ai/glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ]
  }),
});
console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \
-H "Authorization: Bearer $AIMLAPI_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"z-ai/glm-5.3-flash","messages":[{"role":"user","content":"Hello!"}]}'

OpenAI-compatible — swap the base URL and it works with your existing SDK.

GLM-5.3-Flash API Pricing

TypePrice
Input
$0.103155 / 1M tokens
Output
$0.34385 / 1M tokens
Cached input
$0.020631 / 1M tokens

MIT-licensed open weights also available on Hugging Face.

GLM-5.3-Flash vs other models

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