reroute

StepFun: Step 3.5 Flash

stepfun/step-3.5-flash
Compare API Try this model

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....

Modalities
In / Out Price
$0.10 / $0.30 per 1M
Context
262K
Released
Jan 29, 2026
Knowledge Cutoff
—

API

Reroute speaks the OpenAI Chat Completions format. Point any OpenAI SDK at https://www.reroute.wtf/api/v1 and use stepfun/step-3.5-flash as the model.

You need an API key
Keys start with sk-rr-v1- and are shown once.
Create API key
curl https://www.reroute.wtf/api/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $REROUTE_API_KEY" \
  -d '{
  "model": "stepfun/step-3.5-flash",
  "messages": [
    { "role": "user", "content": "What is the meaning of life?" }
  ]
}'

Streaming

Set stream: true to receive server-sent events. The final chunk carries usage and cost.

curl -N https://www.reroute.wtf/api/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $REROUTE_API_KEY" \
  -d '{ "model": "stepfun/step-3.5-flash", "stream": true,
        "messages": [{ "role": "user", "content": "Count to five" }] }'