Limited-time 50% discount via ZAI through September 9, 2026 at 16:00 UTC.

Z.ai: GLM 5.3 Flash

z-ai/glm-5.3-flash

GLM-5.3-Flash is a native multimodal model from Z.ai. It is suited for efficient coding and long-horizon agent tasks. Its hybrid sparse and linear attention architecture maintains accurate long-context behavior while reducing compute overhead.

Modalities

In / Out Price

50% off

$0.075 / $0.25per 1M

Context

Released

Aug 26, 2026

Providers

This model is hosted by one provider. OpenRouter forwards every request to it directly — no routing decisions to make.

Latency / throughput


50% off	$0.15$0.075	$0.50$0.25	$0.03$0.015	3.28s	27 tps	100.00%

Pricing

The average price customers actually pay for this model, next to the prices providers post. Caching and discounts mean the price actually paid is often well below the listed one.

Weighted Average

Weighted Avg Input Price

$0.02348

/M tokens

Weighted Avg Output Price

$0.2621

/M tokens

GLM 5.3 Flash — Price History

$0.02348

$0.2621

$0.075

$0.25

88.3%

100.0%

Uptime

Uptime is the percentage of the past 3 days that at least one provider was responding to requests. Availability is the percentage of time that inference was successfully served. OpenRouter continuously monitors and uses the next-best provider when one returns an error.

Uptime (3d)

99.91%

Availability (3d)

99.62%

Availability over the last 3 days

Aug 24, 12 AM - Aug 27, 12 AM

Availability 99.62%

MonTueWedNow

Availability over the last 24 hours

OpenRouter Availability

99.53%

When an error occurs in an upstream provider, we can recover by routing to another healthy provider, if your request filters allow it. You can access per-provider uptime data programmatically through the Endpoints API. Learn more about our load balancing and customization options.

Quick Start

Drop-in code to call this model. OpenRouter's API is OpenAI-compatible — most SDKs work by just swapping the base URL. The only thing that changes between models is the model slug below.

Get your API key

Create an API key from your OpenRouter dashboard and set it as an environment variable:

Create API Key

export OPENROUTER_API_KEY=sk-or-v1-...

Make your first request

Use z-ai/glm-5.3-flash with the OpenRouter API:

OpenRouter supports reasoning-enabled models that can show their step-by-step thinking process. Use the reasoning parameter in your request to enable reasoning, and access the reasoning_details array in the response to see the model's internal reasoning before the final answer. When continuing a conversation, preserve the complete reasoning_details when passing messages back to the model so it can continue reasoning from where it left off. Learn more about reasoning tokens.

In the examples below, the OpenRouter-specific headers are optional. Setting them allows your app to appear on the OpenRouter leaderboards.

import { OpenRouter } from "@openrouter/sdk";

const openrouter = new OpenRouter({
  apiKey: "<OPENROUTER_API_KEY>"
});

// Stream the response to get reasoning tokens in usage
const stream = await openrouter.chat.send({
  chatRequest: {
    model: "z-ai/glm-5.3-flash",
    messages: [
      {
        role: "user",
        content: "How many r's are in the word 'strawberry'?"
      }
    ],
    stream: true
  }
});

let response = "";
for await (const chunk of stream) {
  const content = chunk.choices[0]?.delta?.content;
  if (content) {
    response += content;
    process.stdout.write(content);
  }

  // Usage information comes in the final chunk
  if (chunk.usage) {
    console.log("\nReasoning tokens:", chunk.usage.completionTokensDetails?.reasoningTokens);
  }
}

Using third-party SDKs

For information about using third-party SDKs and frameworks with OpenRouter, please see our frameworks documentation.

Enable streaming

Add "stream": true to your request body to receive responses as server-sent events:

curl -N https://openrouter.ai/api/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -d '{
  "model": "z-ai/glm-5.3-flash",
  "stream": true,
  "messages": [
    {"role": "user", "content": "Hello"}
  ]
}'

Endpoint

Sends a request for a model response for the given chat conversation. Supports both streaming and non-streaming modes.

POSThttps://openrouter.ai/api/v1/chat/completions

AuthorizationBearer $OPENROUTER_API_KEY

Content-Typeapplication/json

HTTP-Refereroptional — your site URL, for rankings

X-Titleoptional — your site name, for rankings

Modelz-ai/glm-5.3-flash

Creates a streaming or non-streaming response using the OpenAI Responses API format.

Docs

POSThttps://openrouter.ai/api/v1/responses

AuthorizationBearer $OPENROUTER_API_KEY

Content-Typeapplication/json

HTTP-Refereroptional — your site URL, for rankings

X-Titleoptional — your site name, for rankings

Modelz-ai/glm-5.3-flash

Creates a message using the Anthropic Messages API format. Supports text, images, PDFs, tools, and extended thinking.

Docs

POSThttps://openrouter.ai/api/v1/messages

AuthorizationBearer $OPENROUTER_API_KEY

Content-Typeapplication/json

HTTP-Refereroptional — your site URL, for rankings

X-Titleoptional — your site name, for rankings

Modelz-ai/glm-5.3-flash

Parameters

Name	Type	Default	Description
`reasoning`	map	—	Controls reasoning behavior for models that support thinking tokens, including whether reasoning is enabled, the reasoning effort, maximum reasoning tokens, and whether reasoning is excluded from the response.
`max_tokens`	integer	—	This sets the upper limit for the number of tokens the model can generate in response.
`temperature`	float	`1`	This setting influences the variety in the model's responses.
`top_p`	float	`0.95`	This setting limits the model's choices to a percentage of likely tokens: only the top tokens whose probabilities add up to P.
`tools`	array	—	Tool calling parameter, following OpenAI's tool calling request shape.
`tool_choice`	string or object	—	Controls which (if any) tool is called by the model.
`top_k`	integer	`0`	This limits the model's choice of tokens at each step, making it choose from a smaller set.
`response_format`	map	—	Forces the model to produce specific output format.

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Z.ai: GLM 5.3 Flash

z-ai/glm-5.3-flash

Providers

Pricing

Weighted Average

GLM 5.3 Flash — Price History

Performance

Uptime

Availability over the last 3 days

Availability over the last 24 hours

Apps

Activity

Quick Start

Get your API key

Make your first request

Using third-party SDKs

Enable streaming

Endpoint

Parameters

Frequently asked questions

Explore more models

More models from Z.ai

Z.ai: GLM 5.3 Flash

z-ai/glm-5.3-flash

Providers

Pricing

Weighted Average

GLM 5.3 Flash — Price History

Performance

Uptime

Availability over the last 3 days

Availability over the last 24 hours

Apps

Activity

Quick Start

Get your API key

Make your first request

Using third-party SDKs

Enable streaming

Endpoint

Parameters

Frequently asked questions

Was ZAI GLM-5.3 Flash the stealth model Ox Alpha?

What is GLM 5.3 Flash?

How much does GLM 5.3 Flash cost?

What is the context length of GLM 5.3 Flash?

Does GLM 5.3 Flash support tool calling and structured outputs?

What inputs and outputs does GLM 5.3 Flash support?

What other text models does Z.ai have?

When was GLM 5.3 Flash released?

Explore more models

More models from Z.ai