Step 3.5 Flash 2603 API

CN StepFun

Try in Playground → Get API key

Step 3.5 Flash 2603 is a fast, cost-efficient model from StepFun. Available through the MeshTok unified API.

FastTool Use

Pricing (official list, per 1M tokens)

Input

$0.10/M

Output

$0.30/M

Specifications

Context window256K tokens Input modalitiesText StreamingYes APIOpenAI-compatible

How to use Step 3.5 Flash 2603

Drop-in OpenAI replacement. Change only the base_url and model.

# Python -pip install openai
from openai import OpenAI

client = OpenAI(
    base_url="https://meshtok.com/v1",
    api_key="sk-your-MeshTok-key",
)

resp = client.chat.completions.create(
    model="stepfun/step-3.5-flash-2603",
    messages=[{"role":"user","content":"Hello!"}],
)
print(resp.choices[0].message.content)

# cURL
curl https://meshtok.com/v1/chat/completions \
  -H "Authorization: Bearer sk-your-MeshTok-key" \
  -H "Content-Type: application/json" \
  -d '{"model":"stepfun/step-3.5-flash-2603","messages":[{"role":"user","content":"Hello!"}]}'