# GLM-5.3-Flash

> GLM-5.3-Flash is a Z.ai native multimodal model suited for efficient coding and long-horizon agent tasks.

## Key facts

- Model author: Z.ai
- Input: $0.1143 per 1M tokens (starting price)
- Output: $0.40 per 1M tokens (starting price)
- Cached input: $0.03 per 1M tokens
- Context window: 1,000,000 tokens
- Maximum output: 128,000 tokens
- Input modalities: image, text, video
- Output modalities: text
- Capabilities: reasoning, structured_output, tools
- Released: 2026-08-26
- Model IDs: `jd/glm-5.3-flash`, `z-ai/glm-5.3-flash`
- Model page: https://www.realrelay.ai/model/z-ai/glm-5.3-flash

## Overview

GLM-5.3-Flash is a native multimodal model from Z.ai, suited for efficient coding and long-horizon agent tasks. Its hybrid sparse and linear attention architecture is described as maintaining accurate long-context behavior. Because the model is multimodal from the start, one model can handle screenshots, diagrams and video alongside code and text.

GLM-5.3-Flash has a 1M-token context window and can generate up to 128K output tokens. It accepts text, image and video input and returns text output. It was released on August 26, 2026. Its weights are openly available.

## Capabilities

GLM-5.3-Flash supports reasoning, structured output and tool calling.

## Pricing

GLM-5.3-Flash starts from $0.1143 per 1M input tokens and from $0.40 per 1M output tokens. Cache reads start from $0.03 per 1M tokens. These are starting prices and the rate can vary.

GLM-5.3-Flash is available through RealRelay's OpenAI-compatible API.

## Use cases

Use GLM-5.3-Flash for coding agents that need to look at screenshots, diagrams or video alongside source files, since it accepts image and video input as well as text.

Its 1M-token context window and efficient design also suit long-horizon agent runs that accumulate many tool results over time, with reasoning and structured output available at each step.

## Call it

OpenAI-compatible chat completions:

```bash
curl https://www.realrelay.ai/v1/chat/completions \
  -H "Authorization: Bearer $REALRELAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "z-ai/glm-5.3-flash", "messages": [{"role": "user", "content": "Hello"}]}'
```

## FAQ

### What is GLM-5.3-Flash?

GLM-5.3-Flash is a Z.ai native multimodal model suited for efficient coding and long-horizon agent tasks.

### How much does GLM-5.3-Flash cost?

GLM-5.3-Flash starts from $0.1143 per 1M input tokens and from $0.40 per 1M output tokens, with cache reads from $0.03 per 1M tokens.

### What is the context window of GLM-5.3-Flash?

GLM-5.3-Flash has a 1M-token context window and can generate up to 128K output tokens.

### What inputs and outputs does GLM-5.3-Flash support?

GLM-5.3-Flash accepts text, image and video input and returns text output.

### Does GLM-5.3-Flash support tool calling?

Yes. GLM-5.3-Flash supports tool calling, along with reasoning and structured output.

### When was GLM-5.3-Flash released?

GLM-5.3-Flash was released on August 26, 2026.

### How do I call GLM-5.3-Flash via the API?

Send requests to RealRelay's OpenAI-compatible API and use the model ID z-ai/glm-5.3-flash.