z-ai/glm-5.1GLM-5.1 is Z.ai (Zhipu AI)’s open-weights AI model, released Apr 7, 2026. It costs $1.40/M input and $4.40/M output tokens, and handles a 205K-token context window. Its strongest use case is agentic & tools, where it ranks in the 94th percentile of the models Model Beat tracks.
GLM-5.1 delivers a major leap in coding capability, with particularly significant gains in handling long-horizon tasks.
Scores on standardized evaluations. Higher is better — and rank shows where GLM-5.1 lands among all models tracked on Model Beat.
Graduate-level scientific reasoning
Frontier of human expert knowledge
Common-sense trick questions
Factual accuracy & hallucination
Novel ML problem-solving
Scientific research coding
Real GitHub issue resolution
Human-rated web development
Olympiad-qualifier math
Research-level math problems
Hardest research math
Tool-agent-user reliability
GLM-5.1 delivers a major leap in coding capability, with particularly significant gains in handling long-horizon tasks.
GLM-5.1 is an AI model developed by Z.ai (Zhipu AI), released Apr 7, 2026.
GLM-5.1's list price from Z.ai (Zhipu AI) is $1.40 per million input tokens and $4.40 per million output tokens. The cheapest credible third-party provider on OpenRouter (SiliconFlow) serves it at $1.19/$3.74 per 1M.
GLM-5.1 supports a context window of up to 205K tokens.
On standardized evaluations tracked by Epoch AI, GLM-5.1 scores 97.7% on τ²-bench, 89.9% on GPQA Diamond, 1509 on WebDev Arena.
GLM-5.1 is released with open weights (Open weights (unrestricted)), so the model can be downloaded and self-hosted.
Benchmark data from Epoch AI (CC BY) and Artificial Analysis; pricing, specs & descriptions from OpenRouter. Data updated Sep 17, 2026.