API access, model testing and developer tools for StepFun models.
StepFun Funding History
StepFun develops the Step family of foundation models and a developer platform spanning language, reasoning and speech. Founded in Shanghai by former Microsoft vice president Jiang Daxin, it combines model research with deployment through consumer devices, automotive partners and developer APIs.
Company Overview
StepFun
Founded 2023 · Shanghai, China
Official WebsiteStepFun Funding Timeline
Series B+
More than RMB 5 billion
StepFun disclosed this Series B+ in 2026-01-26. Financial terms are presented as disclosed in the linked announcement. The announcement names additional investors; displayed investor identities are partial.
Participation included Tencent, Qiming Venture Partners, 5Y Capital.
Source · finance.sina.com.cn ↗Series B
Hundreds of millions of US dollars
Month precision; report published December 26 refers to an investor post earlier that week. Exact amount undisclosed.
Led by Fortera Capital. Participation included Tencent, Qiming Venture Partners.
Source · scmp.com ↗
StepFun Founding Team
Founder and CEO Jiang Daxin leads StepFun alongside chairman Yin Qi. The May 2026 company account also identifies Zhang Xiangyu as chief scientist and Zhu Yibo as chief technology officer.
StepFun Company Development
A Foundation-Model Company Built by a Microsoft Veteran
Jiang Daxin established StepFun in April 2023. The Shanghai company pursued multimodal foundation models and consumer applications, with its December 2024 Series B supporting further work in multimodality and complex reasoning.
New Funding and Leadership Reinforce Terminal Deployments
StepFun completed a Series B+ exceeding RMB 5 billion in January 2026, with existing investors including Tencent, Qiming and 5Y Capital participating. Yin Qi, founder of Megvii, became chairman. The company’s commercialization strategy extends to personal devices, smart vehicle cockpits and embodied intelligence.
Open Model Releases Complement the API Business
StepFun distributes models through its official Hugging Face organization as well as a paid developer platform. Step 3.5 Flash provides a public-weight release, while the current platform highlights Step 5 Preview, StepAudio 3 Realtime and Step Plan subscriptions for developers building real-world applications.
FAQ
Who founded StepFun?
Jiang Daxin, formerly a Microsoft vice president, founded StepFun in Shanghai in April 2023.
What does StepFun build?
StepFun develops foundation models and developer services for language, reasoning, speech and multimodal applications.
Who is Yin Qi at StepFun?
The Megvii founder became StepFun’s chairman in January 2026, with responsibility for its broader strategy and technological direction.
Has StepFun completed its reported $2.5 billion round?
The May 2026 report reviewed here described a round nearing completion and said StepFun had not commented. It is not treated as completed financing.
Does StepFun release model weights?
Yes. Its official Hugging Face organization distributes releases including Step 3.5 Flash, alongside the company’s hosted developer platform.