Step 3.5 Flash

stepfun/step-3-5-flash

MoE model (196B total, 11B active) with strong reasoning and 256K context. Free tier.

Specifications

Context Window 256K tokens

Max Output 8.2K tokens

Latency fast

Knowledge Cutoff

Training Data

Pricing

Input $0.00 per 1M tokens

Output $0.00 per 1M tokens

Capabilities

text Text generation and understanding

reasoning Advanced multi-step reasoning with chain-of-thought

API Identifiers

Model ID stepfun/step-3-5-flash

Provider API ID step-3-5-flash

Usage via Multi-Router

curl https://api.multi-router.ai/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "x-mr-router-id: YOUR_ROUTER_ID" \
  -d '{
    "model": "stepfun/step-3-5-flash",
    "messages": [
      {"role": "user", "content": "Hello!"}
    ]
  }'