Grok 2 vs Step-3.5-Flash

Grok 2

xAI

Grok 2, released by xAI in August 2024, is a large language model with 131K token context window and native image understanding, developed with access to real-time information from the X platform. It features multimodal input capabilities and improved reasoning over its predecessor. Grok 2 targets conversational assistants, image analysis, and real-time information retrieval tasks via the xAI API.

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.