Z.ai: GLM 5.3 API
GLM-5.3 uses the same base model as GLM-5.2 — every gain comes from post-training. Compared with GLM-5.2, it is much better at complex coding and long-horizon tasks
- Context window: 1,000,000 tokens
- Max output: 128,000 tokens
- Input: text
- Output: text
- Reasoning: Supported
- Tool calling: Supported
- Released: 2026-08-27
Frequently Asked Questions
What is the context window of GLM 5.3?
GLM 5.3 supports a context window of up to 1,000,000 tokens.
Does GLM 5.3 support function calling?
Yes. GLM 5.3 supports tool / function calling.
Does GLM 5.3 support reasoning?
Yes. GLM 5.3 is a reasoning-capable model.