Provider - 5 models
StepFun API models
The registry lists 5 StepFun models with first-party API prices, context windows and release dates. The newest is Step 3.7 Flash, released May 29, 2026. Step 3.5 Flash has the lowest output price at $0.30 per 1M tokens ($0.10 input). The largest context window is 1,000,000 tokens, on Step 5 Preview. 3 of the 5 publish open weights.
Last verified . Sources
- Models
- 5
- Lowest output / 1M
- $0.30
- Largest context
- 1M
- Open weights
- 3 of 5
Every StepFun model
| Model | API model id | Input / 1M | Output / 1M | Context | Max output | Released | Open weights |
|---|---|---|---|---|---|---|---|
| Step 3.7 Flash | step-3.7-flash | $0.20 | $1.15 | 256K | - | Yes | |
| Step 3.5 Flash | step-3.5-flash | $0.10 | $0.30 | 256K | - | - | Yes |
| Step 3.5 Flash 2603 | step-3.5-flash-2603 | $0.10 | $0.30 | 256K | - | - | No |
| Step 5 Preview | step-5-preview | $1 | $2.70 | 1M | 64K | - | Yes |
| Step-1o Turbo Vision | step-1o-turbo-vision | $0.36 | $1.15 | 32K | - | - | No |
Prices in USD per 1M tokens at the standard rate, newest release first. A dash means no primary page states that fact. Open a model for cache, batch and long-context rates.
Capabilities
| Model | Tool calling | Structured outputs | Image input | Audio input | Prompt caching | Batch API | Reasoning |
|---|---|---|---|---|---|---|---|
| Step 3.7 Flash | Yes | Yes | Yes | Not stated | Yes | Not stated | Yes |
| Step 3.5 Flash | Yes | Yes | No | No | Yes | Not stated | Yes |
| Step 3.5 Flash 2603 | Yes | Yes | No | No | Yes | Not stated | Yes |
| Step 5 Preview | Yes | Yes | Yes | No | Yes | Not stated | Yes |
| Step-1o Turbo Vision | Not stated | Not stated | Yes | Not stated | Yes | Not stated | Not stated |
From each model's API docs; open a model for the source behind every answer. Not stated means the provider's docs do not say either way. It is not the same as No. Compare every provider.
Limits and benchmarks
FAQ
What is the cheapest StepFun model?
By output price, Step 3.5 Flash is the cheapest StepFun model in the registry at $0.30 per 1M output tokens and $0.10 per 1M input tokens, per platform.stepfun.ai on October 17, 2026. Step 3.5 Flash 2603 is listed at the same price.
Which StepFun model has the largest context window?
Step 5 Preview has the largest context window of the 5 StepFun models in the registry, at 1,000,000 tokens.
What is the newest StepFun model?
Step 3.7 Flash is the most recent StepFun release in the registry, released on May 29, 2026. 4 of the 5 StepFun models have no primary-sourced release date, so they are not counted.
Which StepFun models have open weights?
3 of the 5 StepFun models in the registry publish open weights: Step 3.7 Flash, Step 3.5 Flash and Step 5 Preview.
Sources
Prices last verified from platform.stepfun.ai.
Further primary sources (13)
- https://platform.stepfun.ai/docs/en/guides/models/step-3.7-flash
- https://platform.stepfun.ai/docs/en/guides/models/overview
- https://static.stepfun.com/blog/step-3.7-flash/
- https://huggingface.co/stepfun-ai/Step-3.7-Flash
- https://platform.stepfun.ai/docs/en/guides/models/step-3.5-flash
- https://static.stepfun.com/blog/step-3.5-flash/
- https://huggingface.co/stepfun-ai/Step-3.5-Flash
- https://platform.stepfun.ai/docs/en/api-reference/chat/chat-completion-create
- https://platform.stepfun.ai/docs/en/guides/models/step-5-preview
- https://www.stepfun.com/step-5-preview
- https://huggingface.co/stepfun-ai/Step-5-Preview
- https://huggingface.co/stepfun-ai/Step-5-Preview/blob/main/LICENSE.txt
- https://platform.stepfun.ai/docs/en/guides/model-migration
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