GLM-5.3 API
GLM-5.3 is Zhipu's latest text-only flagship for complex software engineering and agent tasks. It uses the same base model as GLM-5.2 and gains its improvements from post-training, with a 1M context, 128K output, always-on thinking and low/high/max reasoning effort.
Official source: model page · verified 2026-10-22
Pricing
Prices can change with upstream providers; the rate at settlement is authoritative.
Call the API
Use the OpenAI-compatible endpoint; no model-specific SDK setup is required.
curl https://api.kimiseek.app/v1/chat/completions \
-H "Authorization: Bearer $KIMISEEK_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "glm-5.3",
"messages": [{"role": "user", "content": "Hello from KimiSeek"}]
}'Where it fits
Best for
- Complex software engineering and CLI agents
- Long-horizon coding and tool workflows
- Security and vulnerability analysis
Tradeoffs
- Text-only; no image or video input
- Thinking cannot be disabled; choose low/high/max effort explicitly
Model details
FAQ
What changed from GLM-5.2?
Zhipu reports a 50% gain on its internal Z.ai Code Bench and stronger results on Terminal Bench 3.0 and Agents' Last Exam (CLI).
Does GLM-5.3 support disabling thinking?
No. The official page says thinking is always enabled; set reasoning_effort to low, high or max.
How do I call this model?
Use KimiSeek's OpenAI-compatible API and set the model field to glm-5.3 with your KimiSeek API key.