
Z.ai API Developer Guide 2026: GLM-5.3 Endpoints, Key Types and Error Codes
Z.ai is Zhipu AI’s international developer platform for the GLM model family, exposing the models through both an Anthropic-compatible and an OpenAI-compatible API (quick start). As of October 2026, the current flagship is GLM-5.3 with the cheaper GLM-5.3-Flash alongside it, and the GLM Coding Plan has moved from quarterly tiers to a credits-based subscription that the vendor advertises as starting at 18 USD per month (plan overview). This revision re-opened the vendor’s own pages on 2026-10-29 and did two things the earlier version did not: it added the key-type rules that took effect on 2026-10-16, and it added the error-handling section a developer needs when a request fails. Endpoints, model names and prices were re-checked rather than rewritten. ...


