Doubao 1.5 Vision Pro vs Step-3.5-Flash

ByteDance

Doubao 1.5 Vision Pro, released by ByteDance via Volcano Engine on January 22, 2025, is a multimodal large language model from the Doubao 1.5 family with comprehensive upgrades to visual reasoning, OCR, and fine-grained image understanding. Built on a large-scale sparse MoE architecture, it targets vision-intensive workflows including document analysis, chart interpretation, and visual question answering.

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.