GLM 5.3 Fast

zai/glm-5.3-fast

A chat model with a 1M-token context window, at $2.205 per million input tokens and $6.93 per million output tokens.

Details

Maker: zai
Kind: Chat
Context window: 1,048,576 tokens
Max output: 262,144 tokens
Input: $2.205 per million tokens
Cached input: $0.2205 per million tokens, 90% off
Cache write: Same as input
Output: $6.93 per million tokens
Capabilities: Reasoning, tool use
Takes: Text
Returns: Text
Zero data retention: Yes, on every provider
No training on requests: Yes, on every provider
Released: 2026-09-02

Description

Speed-optimized version of Z.AI’s GLM-5.3 agentic coding model, built for responsive, real-time workloads. It supports advanced coding, long-horizon task execution, testing, vulnerability discovery, and cybersecurity analysis, making it ideal for developer tools, coding agents, and complex multi-step engineering workflows.

Call it

curl

curl https://phantom.codes/v1/chat/completions \
  -H "Authorization: Bearer $PHANTOM_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "zai/glm-5.3-fast",
    "messages": [
      {"role": "user", "content": "Hello"}
    ]
  }'

Set PHANTOM_KEY to your key. Any OpenAI client works with the base URL https://phantom.codes/v1.

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