Stepfun (StepFun) is a Shanghai AI lab shipping the Step language model series and the Step1X-Image / Step-Video generators. Several Step models are released under open weights.
Visit StepfunModels tracked
3
Open weight
1
API only
2
Avg score
55.5
Top benchmark
75.2
Arena Score
Total HF downloads
100.0
Context window
16K
First release
Nov 2024
Latest release
May 2025
Ranked by composite score across benchmarks, popularity, efficiency, and versatility.
| # | Model | Modality | Score | Params | Released |
|---|---|---|---|---|---|
| 1 | text | BB57.6 | — | May 2025 | |
| 2 | text | BB55.2 | — | Nov 2024 | |
| 3 | image | CC53.8 | — | Apr 2025 |
The strongest model from this provider in each modality. Click a card to open the model page.
How this provider’s catalog splits across text, image, video, audio, and embedding.
When each model shipped, newest first.
May 31
Apr 25
Nov 30
Composite grades across this provider’s catalog. Higher is better, blending benchmarks, popularity, and efficiency.
Models with downloadable weights, ranked by composite score.
| # | Model | Modality | Score | Params | Released |
|---|---|---|---|---|---|
| 1 | image | CC53.8 | — | Apr 2025 |
Closed-source models accessed through Stepfun’s API.
API pricing is per million tokens unless noted otherwise.
| # | Model | Modality | Score | Params | Released |
|---|---|---|---|---|---|
| 1 | text | BB57.6 | — | May 2025 | |
| 2 | text | BB55.2 | — | Nov 2024 |
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