StepFun

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: platform.stepfun.ai
Model page: stepfun.com/step-5-preview

Open weights on Oct 15.

Great to be at AI Engineer Shanghai 2026!

Thanks to everyone who stopped by our booth! It was great connecting with developers, sharing live demos, and exchanging ideas on long-horizon agents and the future of agentic AI.

Our very own Ailing Teng @EileenTal also took the stage to share how Step 5 Preview and our open-source Agent Harness, Step Code, work together to help agents stay on track and reliably execute long-horizon tasks.

We really appreciated all the thoughtful conversations throughout the event.

Stay tuned for what we're building next!

Rain couldn't stop the builders.

Great conversations at our Step 5 Preview Launch Night with @togethercompute!

From long-horizon agents and tool-calling reliability to inference costs and what AI breakthroughs mean for the next wave of startups.

Huge thanks to our panelist Dan Fu (@realDanFu · @togethercompute), Mar Hershenson (@MarHershenson · @pearvc), Saoud Rizwan (@sdrzn · @cline), and Joey Wang (@harvey), and everyone who joined us!

More to come.

StepFun is at #AGNTCon + #MCPCon North America!

📍 Find us at Booth #24!

If you’re attending, stop by to say hi, catch up, and connect with our team. We’d love to exchange ideas with fellow builders and explore the future of AI agents together.

See you there! 🤝

What a weekend at LA Hacks 2026!

Beyond connecting with the community at our booth, we hosted a hands-on workshop to help participants get started with Step 5 Preview and explore what they could build with it.

We also launched the StepFun Challenge and saw teams made especially thoughtful and effective use of our models.

Huge thanks to everyone who stopped by, joined our workshop, or took on the challenge. Congrats to our three winning teams!

We loved being part of LA Hacks and can't wait to see what you build next.