StepFun: Step 5 Preview
Step 5 Preview is a reasoning model from StepFun released on Sep 16, 2026. It reads text, images and video and writes text, with a 1M token context window and up to 66K tokens per reply.
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It costs $0.959 per million input tokens and $2.74 per million output tokens. Cached input bills at $0.048, 95% less than fresh input.
It supports tool calling, structured JSON output and prompt caching.
11 providers serve it, including Novita AI, Vercel AI Gateway and EmpirioLabs AI.
- Modalities
- In / out price
- $0.959 / $2.74 per 1M
- Context
- 1M
- Max output
- 66K
- Released
- Sep 16, 2026
- Knowledge cutoff
- n/a
- Tool calling
- Structured output
- Reasoning
- Prompt caching
- Open weights
- Free to use
Step 5 Preview pricing
USD, as listed on Oct 15, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.
| Input | $0.959 / 1M tokens | |
|---|---|---|
| Output | $2.74 / 1M tokens | |
| Cached input (read) | $0.048 / 1M tokens | 95% off input |
Step 5 Preview providers
11 providers serve it, including Novita AI, Vercel AI Gateway and EmpirioLabs AI. Each host sets its own price and limits, so the cheapest one is not always the one with the longest context.
| Provider | Input /M | Output /M | Cache read /M | Context | Max output |
|---|---|---|---|---|---|
| StepFun (China) First party | $0.959 | $2.74 | $0.048 | 1M | 66K |
| Novita AI | $1 | $2.70 | $0.10 | 1M | 64K |
| Vercel AI Gateway | $1 | $2.70 | $0.05 | 1M | 1M |
| EmpirioLabs AI | $1 | $2.70 | $0.05 | 1.02M | 131K |
| Kilo Gateway | $1 | $2.70 | $0.05 | 1M | 64K |
| NanoGPT | $1 | $2.70 | $0.05 | 1M | 1M |
| StepFun (Global) | $1 | $2.70 | $0.05 | 1.02M | 66K |
| AIHubMix | $1.08 | $3.09 | $0.054 | 1M | 1M |
| AI/ML API | $1.38 | $3.71 | $0.0688 | 1M | 64K |
| StepFun Step Plan (China) | n/a | n/a | – | 1M | 66K |
| StepFun Step Plan (Global) | n/a | n/a | – | 1M | 66K |
What Step 5 Preview costs per month
Pick a workload close to yours or type your own volumes.
Supported request parameters
What you can set when you call Step 5 Preview through an OpenAI compatible API.
- Tools
tools - Structured outputs
structured_outputs - Reasoning
reasoning
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Step 5 Preview questions
How much does the Step 5 Preview API cost?
$0.959 per million input tokens and $2.74 per million output tokens, with cached input at $0.048. The estimator on this page turns that into a monthly bill for your own workload.
What is the context window of Step 5 Preview?
1,000,000 tokens of input, and it can write up to 65,536 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.
Which providers serve Step 5 Preview?
11 providers serve it, including Novita AI, Vercel AI Gateway and EmpirioLabs AI. Prices differ by host, so the Providers table on this page lists each one with its input and output price.
Does Step 5 Preview support tool calling?
Yes. It accepts tool definitions and can return JSON that matches a schema, which is what an agent needs to call your APIs.
Is Step 5 Preview open source?
No. StepFun serves it through an API only, so you cannot download the weights or host it yourself.
When was Step 5 Preview released?
Sep 16, 2026.
Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 15, 2026. The summary is written from these facts.