# StepFun: Step 3.5 Flash

- Model id: `stepfun/step-3.5-flash`
- Served by: -
- List price per 1M tokens, input / output, from: -, with 0% platform fee. A request is billed at the list price of the host that served it.
- Context: 262K, max output 66K
- Prices read 2026-11-15 09:33 UTC
- Page: https://plaingateway.com/models/stepfun/step-3.5-flash

Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....

## Hosts

| Host | Endpoint | In / out /M | Cache read /M | Context | Served |
|---|---|---|---|---|---|
| Siliconflow | `siliconflow/fp8` | $0.10 / $0.30 | - | 262K | no |

## First request

```sh
curl https://api.plaingateway.com/api/v1/chat/completions \
  -H "Authorization: Bearer $PLAINGATEWAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "stepfun/step-3.5-flash", "messages": [{"role": "user", "content": "Say hello in five words."}]}'
```

Sign up at https://plaingateway.com/signup (no card), create a key, send a test call, and add credits when you want more. New accounts may get a small starting credit. The whole bootstrap for agents: https://plaingateway.com/llms.txt