Z AI drops GLM-5.1, open source coming in April

Z AI has rolled out GLM-5.1 to all users on its GLM Coding Plan, the company's subscription tier aimed at developers and agentic workflows. The update lands quietly — no benchmark dump, no spec sheet — but the accompanying commitment matters: GLM-5.1 will be open-sourced by mid-April 2026.

This signals a direct response to community anxiety. When Z AI shipped the closed-source GLM-5-Turbo in mid-March with no open-source commitment, many feared the company was pivoting away from the MIT-licensed approach that built its reputation. The predecessor, GLM-5, is a 744B MoE model (40B active params) trained entirely on Huawei Ascend chips — no NVIDIA dependency.

No architecture changes or new benchmarks have been disclosed yet for 5.1. It reads as an incremental coding improvement ahead of a full open release.

Why it matters: if GLM-5.1 open-sources on schedule, it'll be one of the most capable freely available coding models — and a rare one with zero NVIDIA provenance.