Step 3.5 Flash Base Midtrain
StepFun publishes Base-Midtrain as a separate checkpoint in the Step 3.5 Flash line. Its card points to the same open training project and sparse model architecture as the Base release.
Research release
Keep the checkpoint identity
The published repository is specifically named Base-Midtrain. The card includes family-wide claims about the finished Flash model; it does not establish that this training stage delivers those same results.StepFun Step-3.5-Flash-Base-Midtrain model card
Use it for a controlled training comparison
Practical guidance. Choose this checkpoint when the training stage is part of your experiment. Record it separately from Base and the completed model. Comparing checkpoints under the same prompts can help isolate the effect of later training.
Specifications & access
| Detail | Value and conditions |
|---|---|
| Status | Research release |
| Access | Downloadable |
| Model identifiers | Step-3.5-Flash-Base-Midtrain |
| License | Apache 2.0.StepFun Step-3.5-Flash-Base-Midtrain model card |
| Release type | A named intermediate training checkpoint, not a hosted chat model ID.StepFun Step-3.5-Flash-Base-Midtrain model card |
Related models
- Step 3.5 Flash
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Step 3.5 Flash is a text reasoning model for code and tool use.
Launch date not confirmedAPI · Downloadable - Step 3.5 Flash Base
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A pretrained sparse language-model checkpoint from the Step 3.5 Flash family.
Launch date not confirmedResearch releaseDownloadable