Xiuyu Li(@sheriyuo):We’ve been quiet for too long. It’s time for a change. Over the past few months, we’ve been pushing toward the frontier, step by step. And now, things are finally coming together. Welcome to StepFun. Come build better open models and more general agents with us!

2026.09.20 03:45

We’ve been quiet for too long. It’s time for a change. Over the past few months, we’ve been pushing toward the frontier, step by step. And now, things are finally coming together. Welcome to StepFun. Come build better open models and more general agents with us!

StepFun@StepFun_ai

2026.09.20 03:15

Introducing Step 5 Preview: Advancing the Pareto Frontier. Step 5 Preview is our new flagship model for agentic work, delivering frontier-level performance across software engineering and professional knowledge work, with particular strength in finance. - 600B total / 27B active MoE, with 1M context + Vision - Substantially lower task cost at comparable intelligence - Broad software engineering capabilities with sustained execution over long horizons Try Step 5 Preview: Model page: Open weights on Oct 15.