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GLM 5.3 Flash

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glm-5.3:flash

glm-5.3flashFP8ImageToolsReasoning

GLM 5.3 Flash from Z.ai, a fast model with a 1M-token context window. Supports image input, tool calling, JSON output, streaming and adjustable reasoning effort.

When to choose GLM 5.3 Flash

GLM 5.3 Flash is a fast open-weight model from Z.ai with one of the two largest context windows in the Tokener CA catalog. It reads text and images, calls tools and returns JSON, which makes it a good default for agents that must keep a lot of material in view at once.

It is a strong fit for:

  • Long inputs — whole codebases, long documents, transcripts and log files in a single request.
  • Long-running agents — many turns of tool results and history before anything has to be trimmed.
  • Document and screenshot questions — pulling facts out of pages, charts and UI captures.
  • Structured output — JSON and code that another program consumes.

You choose how much it reasons

Reasoning on this model cannot be switched off, but you choose the effort: low (the default, the quickest and cheapest), medium or high. A request that asks for reasoning off gets the low effort, which keeps thinking to a minimum. Reasoning tokens are billed as output tokens. See Reasoning controls.

How it compares

DeepSeek V4.1 Flash has the same large context window and can turn reasoning off completely, but reads text only. For agentic coding on smaller inputs, compare Qwen3.8 27B and Ornith 1.5 35B. For quick, high-volume text tasks, Nemotron 3.5 Lightning 30B is the budget choice.

Pricing

10% offuntil Oct 13, 2026, 6:51 PM EDT
Input (per 1M tokens)Regular price US$0.15 / M TokensLimited-time price US$0.135 / M Tokens
Output (per 1M tokens)Regular price US$0.70 / M TokensLimited-time price US$0.63 / M Tokens
Cache read (per 1M tokens)Regular price US$0.03 / M TokensLimited-time price US$0.027 / M Tokens

You pay only for the tokens you use. How billing works.

Specifications

Context window1M tokens
Max output1M tokens
InputText, Image
OutputText
ReasoningLow, Medium, High (default Low)

Performance

Latency 0.5 s

Throughput 155 tok/s · measured Oct 4, 2026

Latency and throughput: median of the last 10 test requests from our server.

Uptime 100.0 % · last 3 days

Share of our automatic test requests in the last 3 UTC days (today so far and the two days before) that got a complete answer. We send them about every 30 minutes from our server to the suppliers your requests use by default; supplier timeouts and rate limits count as failures. A short outage between two checks can be missed.

Quick start

Call GLM 5.3 Flash through the OpenAI-compatible API at https://a.tokener.ca/v1, or the Anthropic-compatible (Messages) API at https://a.tokener.ca (no /v1), with the model id glm-5.3:flash.

curl https://a.tokener.ca/v1/chat/completions \  -H "Authorization: Bearer $TOKENER_API_KEY" \  -H "Content-Type: application/json" \  -d '{    "model": "glm-5.3:flash",    "messages": [{"role": "user", "content": "Hello!"}],    "stream": true  }'

Other protocols

The same model, key and price are available on the OpenAI Responses and Anthropic-compatible (Messages) protocols. For the Anthropic SDKs, use the base URL https://a.tokener.ca (without /v1).

OpenAI Responses — guide

curl https://a.tokener.ca/v1/responses \
  -H "Authorization: Bearer $TOKENER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "glm-5.3:flash",
    "input": [{"role": "user", "content": [{"type": "input_text", "text": "Hello!"}]}],
    "stream": false
  }'

Anthropic-compatible (Messages) — guide

curl https://a.tokener.ca/v1/messages \
  -H "x-api-key: $TOKENER_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "glm-5.3:flash",
    "max_tokens": 4096,
    "messages": [{"role": "user", "content": [{"type": "text", "text": "Hello!"}]}],
    "stream": false
  }'

Questions

How much does GLM 5.3 Flash cost?

GLM 5.3 Flash costs US$0.15 per 1M input tokens and US$0.70 per 1M output tokens. Cached input tokens are US$0.03 per 1M. You pay only for the tokens you use.

What is the context window of GLM 5.3 Flash?

GLM 5.3 Flash has a context window of 1,048,576 tokens. It can return up to 1,048,576 output tokens.

Does GLM 5.3 Flash accept Image input?

Yes — GLM 5.3 Flash accepts Image input in addition to text.

Can I control reasoning on GLM 5.3 Flash?

Yes — GLM 5.3 Flash supports these reasoning settings: Low, Medium, High. The default is Low. You choose it per request.

Is GLM 5.3 Flash OpenAI-compatible?

Yes — call GLM 5.3 Flash through Tokener's OpenAI-compatible API at https://a.tokener.ca/v1 with the model id glm-5.3:flash. Both OpenAI protocols work: Chat Completions at https://a.tokener.ca/v1/chat/completions and OpenAI Responses at https://a.tokener.ca/v1/responses. Any OpenAI-compatible client or SDK works.

Can I use GLM 5.3 Flash with the Anthropic SDK?

Yes — GLM 5.3 Flash is available on the Anthropic-compatible Messages API at https://a.tokener.ca/v1/messages. Point the Anthropic SDK at the base URL https://a.tokener.ca (without /v1 — the SDK appends it) and use the model id glm-5.3:flash. Which features work varies by model; see the Anthropic SDK guide at /docs/anthropic-sdk.

How do I try GLM 5.3 Flash?

Create an API key, add credits, and call the endpoint with the model id glm-5.3:flash — or try GLM 5.3 Flash in the Tokener Playground.

Try in PlaygroundGet an API keyIntegration docsAll models