Z.ai is an AI assistant and platform from the Chinese company Z.AI Co., Ltd. (Beijing, China), which operates internationally under the Z.ai brand. The company has academic roots (it grew out of a Tsinghua University group) and develops the GLM family of models, including the open-weights GLM-5.3 and GLM-5.3-Flash. The Z.ai brand is part of the ecosystem of the Chinese company Zhipu AI/Z.AI Co., Ltd.
What it does
- Conversations, answers and research with the assistant (web chat and app)
- Assisted coding and coding agents (GLM Coding Plan, IDE and dev-tool integrations)
- Agent tasks and automation (deep research, website and deck creation)
- Multimodal analysis with GLM-5.3-Flash (images, videos and files)
- API access for developers
How it works
- You use the chat at z.ai (defaults to GLM-5.3-Flash) or the API
- GLM models process with multi-step reasoning and long context (up to 1 million tokens)
- Coding plans (GLM Coding Plan) connect the models to agents and IDEs through a points system
- The API covers text, vision and other GLM family capabilities
Models
The GLM family is developed by Z.ai. GLM-5.3 is the flagship open-weights model, focused on coding and agents, with a 1-million-token context and text input. GLM-5.3-Flash is the first natively multimodal model in the series (320B parameters, 18B active), with video, image, text and file input. The family also includes GLM-5.2, GLM-5.1, GLM-4.x, vision models, OCR, audio, and image/video generation available via API.
Public pricing
- Free chat available on the website (z.ai)
- Pay-as-you-go API (per 1 million tokens; some family models have a free tier)
- GLM Coding Plan with paid plans starting at US$ 18/month, for use in coding agents and IDEs
- No paid plan is documented for the general chat beyond free access and the API
Strengths
- Competitive open-weights models for coding and agents
- Long context (1 million tokens) and multimodality on Flash
- Broad API with public pricing
- Aggressive value on the Flash models
Points of attention
- Chinese company: review data and regulatory policies for professional use
- Brand and portfolio in transition; models and plans change quickly
- Benchmark and performance claims come from the company (e.g. Z.ai Code Bench, public benchmark results) — verify before citing as fact
- International availability of the app and API may vary by region