StepFun

Scale-up possibilities for everyone.
API Platform:

[StepFun @StepFun_ai]

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: https://t.co/fC7HHlWKFn
Model page: https://t.co/4caJR2YGD3

Open weights on Oct 15.

[Together AI @togethercompute]

sf, join us this thursday for step 5 preview launch night with stepfun

we’ll dig into the model, building + serving agent workloads, and what’s worth building as models keep improving, with dan fu, hongyu zhou, mar hershenson, saoud rizwan, joey wang

rsvp: https://t.co/IuQF9QHdT3

[StepFun @StepFun_ai]

@CamilaRivebq9 🔥🔥🔥

[StepFun @StepFun_ai]

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.

[StepFun @StepFun_ai]

@Novatechinfo Yes! Congrats to them

[StepFun @StepFun_ai]

@mdp_sec It was great lol

[StepFun @StepFun_ai]

@shajsjmuwu @togethercompute @realDanFu @MarHershenson Check out our event!

[StepFun @StepFun_ai]

Step 5 Preview weights are out. Now let’s meet in SF.🍷

Join @StepFun_ai and @togethercompute for Step 5 Preview Launch Night & AI Founders Meetup on Thu, Oct 22.

On stage: Hongyu Zhou (@StepFun_ai), Dan Fu (@realDanFu · @togethercompute), Mar Hershenson (@MarHershenson · @pearvc), Saoud Rizwan (@sdrzn · @cline), and Joey Wang (@harvey).

A first look at Step 5 Preview, live Q&A, and a panel on what's still worth building as AI models get better.
Food, drinks & great conversations.

A first look at Step 5 Preview, live Q&A, and a panel on what's still worth building as AI models get better. Food, drinks & great conversations.

Want to join us? Request your spot here: https://t.co/rKNj6sX6eG

[StepFun @StepFun_ai]

@AiwithAlyar @togethercompute @realDanFu @MarHershenson 🔥🫡

[StepFun @StepFun_ai]

@MajeedAGI @togethercompute @realDanFu @MarHershenson There is always opportunity!

[StepFun @StepFun_ai]

@thePandaily @OpenRouter Thank you so much!

[StepFun @StepFun_ai]

@ToviDing @arena @reflection_ai Yes cuz we are steppin up 🔥

[StepFun @StepFun_ai]

@moring_zgmzkym Could you please dm us more details?

[StepFun @StepFun_ai]

LA Hacks 2026, here we come!

StepFun will be at UCLA on Oct 17–18 to meet builders, exchange ideas, and explore what's possible with Step 5 Preview. We'll also host a workshop on Sat, Oct 17, 8–9 PM PT at James West Alumni Center.

Come say hi!

[StepFun @StepFun_ai]

@OHibn98176 Thank you! We really enjoyed it

[StepFun @StepFun_ai]

@mdp_sec 🔥🫡

[StepFun @StepFun_ai]

One week since launch, Step 5 Preview is already #2 on OpenRouter's weekly leaderboard, with 19.5T tokens used.

It has also held #2 on the daily leaderboard since Oct 10.

Thanks to everyone building with us.

[StepFun @StepFun_ai]

@0xSero Appreciate your feedback! We are trying our best🫡

[StepFun @StepFun_ai]

@Korosukevt Happy to hear this🫡

[StepFun @StepFun_ai]

@zzz1465720 🔥🔥

[StepFun @StepFun_ai]

@ArtAnosCranel Thank you for your support as well!

[StepFun @StepFun_ai]

@TechWithSarah Yes!! 🙌