Claude Haiku 4.5 vs Step-3.5-Flash

Claude Haiku 4.5

Anthropic

Claude Haiku 4.5, released by Anthropic in October 2025, is a fast, efficient large language model from the Claude 4.5 family optimized for high-throughput, low-latency workloads. It features a 200K token context window, 64K maximum output tokens, native image understanding, and extended thinking capabilities. Haiku 4.5 targets latency-sensitive applications such as real-time assistants, document classification, and lightweight agentic tasks where rapid response times are a primary requirement.

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.