GLM 5.3 is a balanced model from Z.ai, available here under the exact model id “glm-5.3”. It heads the GLM line-up here, above GLM 5.3 Flash. Z.ai has not published a release date we can cite; it has been available here since 18 Oct 2026.
Z.ai documents tools, reasoning, json mode and prompt caching for it.
It costs $0.396 per million input tokens and $0.77 per million output tokens, so output is 1.9× the input rate. That is 82% below the market rate of $1.40 input and $4.40 output per million tokens, the lowest public price we found at other API gateways. On the use cases below, output makes up 20% of the bill for coding help, 51% for writing and 68% for translation, so capping max tokens and asking for diffs saves more than trimming the prompt. With a 3:1 input-to-output mix it ranks 8th lowest-cost of the 27 models on this site.
Cached input bills at $0.26 per million tokens, 34% below the standard input rate, which pays off when the same system prompt or documents go out on every request.
It is served through the OpenAI-compatible format at https://api.oneaiapikey.com/v1, so any SDK or tool that lets you set a custom base URL, for example Codex CLI, Cursor and Cline, can use it. It is not offered on the Anthropic Messages endpoint; pick an Anthropic-format model for Claude Code.