GLM-4.5 Air vs Step-3.5-Flash

Zhipu AI

GLM-4.5 Air is a lightweight variant from Zhipu AI's GLM-4 model family, designed for efficient deployments requiring lower inference cost while maintaining strong language understanding and generation capabilities. It targets cost-sensitive production workloads, API integrations, and applications where the full GLM-4.x series capacity exceeds requirements.

StepFun

Step-3.5-Flash, released by StepFun on February 2, 2026, is a Mixture-of-Experts large language model with 197 billion total parameters and approximately 11 billion active parameters per inference. It features a 256K token context window using a 3:1 sliding-window-to-full-attention ratio, processing 100–350 tokens per second. Step-3.5-Flash targets agentic tasks, coding workflows, and open-source deployments requiring frontier reasoning capabilities with efficient inference, under an Apache 2.0 license.