Step 3.5 Flash 2603 — Free API

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openrouter/stepfun/step-3.5-flash
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What is Step 3.5 Flash 2603?

Free Step 3.5 Flash 2603 API.

Model ID
stepfun/step-3.5-flash
Base URL
https://openrouter.ai/api/v1

Step 3.5 Flash 2603 API Code Example

Paste your API key and run. See the config generator for Claude Code, Cursor, and more tools.

from openai import OpenAI

client = OpenAI(
    base_url="https://openrouter.ai/api/v1",
    api_key="YOUR_API_KEY"
)

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

const openai = new OpenAI({
  baseURL: "https://openrouter.ai/api/v1",
  apiKey: "YOUR_API_KEY",
});

const completion = await openai.chat.completions.create({
  model: "stepfun/step-3.5-flash",
  messages: [{ role: "user", content: "Hello!" }],
});

console.log(completion.choices[0].message.content);
curl https://openrouter.ai/api/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "stepfun/step-3.5-flash",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

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More About OpenRouter

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