GLM-5.3 Flash

by zai · family glm

Facts

Release date	2026-08-26
Retired date	—
Knowledge cutoff	—
Context (max)	1,310,720
Max output	131,072
Modalities	text, image, video → text
Aliases	`glm-5.3-flash`
Open weights	yes (zai-org/GLM-5.3-Flash)
Description	First natively multimodal GLM-5-series (image/video/file in); 320B/18B-active sparse+linear attention; 1M context; thinking cannot be disabled.

Unknown values are shown as —.

Offerings

Provider	Wire ID	Variant	Endpoint	Protocol	Status	Price (USD / Mtok)	Reasoning
IO Intelligence (io.net)	`zai-org/GLM-5.3-Flash`	flash	chat	openai-chat	ga	0.15 / 0.50	always_on · default on · mandatory · returns reasoning_content
NEAR AI Cloud	`z-ai/glm-5.3-flash`	flash	chat	openai-chat	ga	0.15 / 0.50	always_on · default on · mandatory · returns reasoning_content
Ollama Cloud	`glm-5.3-flash`	flash	v1-chat-completions	openai-chat	ga	—	effort · default on · mandatory · returns hidden
OpenCode Go	`glm-5.3-flash`	flash	go-chat-completions	openai-chat	ga	—	always_on · default on · mandatory · returns reasoning_content · round-trips reasoning_content
OpenCode Zen	`glm-5.3-flash`	flash	chat-completions	openai-chat	ga	0.15 / 0.50	always_on · default on · mandatory · returns reasoning_content · round-trips reasoning_content
OpenRouter	`z-ai/glm-5.3-flash`	flash	chat-completions	openai-chat	ga	0.07 / 0.25	effort · default on · mandatory · returns reasoning_content · round-trips reasoning_content
Z.ai	`glm-5.3-flash`	flash	chat-completions	openai-chat	ga	0.07 / 0.25	toggle · default on · mandatory · returns reasoning_content

Reasoning controls

IO Intelligence (io.net)· zai-org/GLM-5.3-Flash· chat always_on

always_on · default on · mandatory · returns reasoning_content

NEAR AI Cloud· z-ai/glm-5.3-flash· chat always_on

always_on · default on · mandatory · returns reasoning_content

Ollama Cloud· glm-5.3-flash· v1-chat-completions effort

reasoning_effort lowmediumhigh●xhighmax Default level not documented; verify.

effort · default on · mandatory · returns hidden

OpenCode Go· glm-5.3-flash· go-chat-completions always_on

always_on · default on · mandatory · returns reasoning_content · round-trips reasoning_content

OpenCode Zen· glm-5.3-flash· chat-completions always_on

always_on · default on · mandatory · returns reasoning_content · round-trips reasoning_content

OpenRouter· z-ai/glm-5.3-flash· chat-completions effort

reasoning.effort lowmedium●highxhighmax

effort · default on · mandatory · returns reasoning_content · round-trips reasoning_content

Z.ai· glm-5.3-flash· chat-completions toggle

thinking.type on enabled · off

toggle · default on · mandatory · returns reasoning_content

Example requests

IO Intelligence (io.net) · openai-chat · zai-org/GLM-5.3-Flash

curl 'https://api.intelligence.io.solutions/api/v1/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "zai-org/GLM-5.3-Flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ]
}'

Python (requests)

import requests

resp = requests.post(
    "https://api.intelligence.io.solutions/api/v1/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "zai-org/GLM-5.3-Flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ]
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://api.intelligence.io.solutions/api/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "zai-org/GLM-5.3-Flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ]
  }),
})
console.log(await resp.json())

NEAR AI Cloud · openai-chat · z-ai/glm-5.3-flash

curl 'https://cloud-api.near.ai/v1/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "z-ai/glm-5.3-flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ]
}'

Python (requests)

import requests

resp = requests.post(
    "https://cloud-api.near.ai/v1/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "z-ai/glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ]
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://cloud-api.near.ai/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "z-ai/glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ]
  }),
})
console.log(await resp.json())

Ollama Cloud · openai-chat · glm-5.3-flash

curl 'https://ollama.com/v1/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "glm-5.3-flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ],
  "reasoning_effort": "high"
}'

Python (requests)

import requests

resp = requests.post(
    "https://ollama.com/v1/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ],
      "reasoning_effort": "high"
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://ollama.com/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ],
    "reasoning_effort": "high"
  }),
})
console.log(await resp.json())

OpenCode Go · openai-chat · glm-5.3-flash

curl 'https://opencode.ai/zen/go/v1/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "glm-5.3-flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ]
}'

Python (requests)

import requests

resp = requests.post(
    "https://opencode.ai/zen/go/v1/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ]
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://opencode.ai/zen/go/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ]
  }),
})
console.log(await resp.json())

⚠ Responses include reasoning_content artifacts — pass them back unmodified on subsequent turns (dropping them triggers 400s or quality loss).

OpenCode Zen · openai-chat · glm-5.3-flash

curl 'https://opencode.ai/zen/v1/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "glm-5.3-flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ]
}'

Python (requests)

import requests

resp = requests.post(
    "https://opencode.ai/zen/v1/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ]
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://opencode.ai/zen/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ]
  }),
})
console.log(await resp.json())

⚠ Responses include reasoning_content artifacts — pass them back unmodified on subsequent turns (dropping them triggers 400s or quality loss).

OpenRouter · openai-chat · z-ai/glm-5.3-flash

curl 'https://openrouter.ai/api/v1/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "z-ai/glm-5.3-flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ],
  "reasoning": {
    "effort": "medium"
  }
}'

Python (requests)

import requests

resp = requests.post(
    "https://openrouter.ai/api/v1/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "z-ai/glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ],
      "reasoning": {
        "effort": "medium"
      }
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://openrouter.ai/api/v1/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "z-ai/glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ],
    "reasoning": {
      "effort": "medium"
    }
  }),
})
console.log(await resp.json())

⚠ Responses include reasoning_content artifacts — pass them back unmodified on subsequent turns (dropping them triggers 400s or quality loss).

Z.ai · openai-chat · glm-5.3-flash

curl 'https://api.z.ai/api/paas/v4/chat/completions' \
  -H 'Authorization: Bearer <YOUR_API_KEY>' \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "glm-5.3-flash",
  "messages": [
    {
      "role": "user",
      "content": "Tell me about the weather."
    }
  ],
  "thinking": {
    "type": "enabled"
  }
}'

Python (requests)

import requests

resp = requests.post(
    "https://api.z.ai/api/paas/v4/chat/completions",
    headers={
      "Authorization": "Bearer <YOUR_API_KEY>",
      "Content-Type": "application/json"
    },
    json={
      "model": "glm-5.3-flash",
      "messages": [
        {
          "role": "user",
          "content": "Tell me about the weather."
        }
      ],
      "thinking": {
        "type": "enabled"
      }
    },
)
print(resp.json())

TypeScript (fetch)

const resp = await fetch("https://api.z.ai/api/paas/v4/chat/completions", {
  method: "POST",
  headers: {
    "Authorization": "Bearer <YOUR_API_KEY>",
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "model": "glm-5.3-flash",
    "messages": [
      {
        "role": "user",
        "content": "Tell me about the weather."
      }
    ],
    "thinking": {
      "type": "enabled"
    }
  }),
})
console.log(await resp.json())