StepFun

StepFun: Step 3.7 Flash

stepfun/step-3.7-flash

Access Step 3.7 Flash from StepFun using Puter.js AI API.

Get Started 
// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';

puter.ai.chat("Explain quantum computing in simple terms", {
    model: "stepfun/step-3.7-flash"
}).then(response => {
    document.body.innerHTML = response.message.content;
});

<html>
<body>
    <script src="https://js.puter.com/v2/"></script>
    <script>
        puter.ai.chat("Explain quantum computing in simple terms", {
            model: "stepfun/step-3.7-flash"
        }).then(response => {
            document.body.innerHTML = response.message.content;
        });
    </script>
</body>
</html>

# pip install openai
from openai import OpenAI

client = OpenAI(
    base_url="https://api.puter.com/puterai/openai/v1/",
    api_key="YOUR_PUTER_AUTH_TOKEN",
)

response = client.chat.completions.create(
    model="stepfun/step-3.7-flash",
    messages=[
        {"role": "user", "content": "Explain quantum computing in simple terms"}
    ],
)

print(response.choices[0].message.content)

curl https://api.puter.com/puterai/openai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_PUTER_AUTH_TOKEN" \
  -d '{
    "model": "stepfun/step-3.7-flash",
    "messages": [
      {"role": "user", "content": "Explain quantum computing in simple terms"}
    ]
  }'

Model Card

Step 3.7 Flash is a multimodal Mixture-of-Experts model from StepFun, combining a 196B-parameter language backbone with a 1.8B vision encoder and activating roughly 11B parameters per token. It natively processes text and images, supporting a 256K-token context window.

The model is designed for agentic coding, tool orchestration, long-context reasoning, and search-intensive workflows. It exposes tunable reasoning tiers (low, medium, high) so developers can trade inference cost against answer depth on a per-call basis.

Compared to Step 3.5 Flash, Step 3.7 Flash adds native vision input, improves cross-harness consistency, and achieves stronger performance on coding agent and terminal benchmarks. It targets developers building production pipelines that combine perception, retrieval, and multi-step execution.

Context Window 256K

tokens

Max Output 256K

tokens

Input Cost $0.2

per million tokens

Output Cost $1.15

per million tokens

Release Date May 28, 2026

 

Output Speed 356

tokens / sec

Latency 0.84s

time to first token

Model Playground

Try Step 3.7 Flash instantly in your browser.
This playground uses the Puter.js AI API — no API keys or setup required.

Chat stepfun/step-3.7-flash
StepFun
Chat with Step 3.7 Flash
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Benchmarks

How Step 3.7 Flash performs on standard evaluations.

Artificial Analysis
Intelligence Index
42.6
Better than 87% of tracked models
Artificial Analysis
Coding Index
37.1
Better than 83% of tracked models
BenchmarkScore
GPQA Diamond Graduate-level science Q&A
80.9%
Humanity's Last Exam Cross-domain reasoning
19.9%
SciCode Scientific programming
40.0%
IFBench Instruction following
67.3%
LCR Long-context reasoning
63.7%
Terminal-Bench Hard Agentic terminal tasks
35.6%
τ²-Bench Tool use / agents
98.5%

Scores sourced from Artificial Analysis.

Find other StepFun models →

Chat

Step 3.5 Flash

Step 3.5 Flash is an open-source reasoning model from StepFun, built on a sparse Mixture-of-Experts (MoE) architecture with 196B total parameters but only 11B active per token. It supports a 256K-token context window and native tool calling. The model is purpose-built for agentic and coding workflows, with generation throughput of 100–300 tokens/sec in typical usage. It scores 74.4% on SWE-bench Verified, 97.3 on AIME 2025, 86.4% on LiveCodeBench-V6, and 88.2 on τ²-Bench. Step 3.5 Flash is a strong choice for developers building AI agents, code assistants, or multi-step reasoning pipelines who need frontier-level intelligence at low per-token cost.

Frequently Asked Questions

How do I use Step 3.7 Flash?

You can access Step 3.7 Flash by StepFun through Puter.js AI API. Include the library in your web app or Node.js project and start making calls with just a few lines of JavaScript — no backend and no configuration required. You can also use it with Python or cURL via Puter's OpenAI-compatible API.

Is Step 3.7 Flash free?

Yes, it is free if you're using it through Puter.js. With the User-Pays Model, you can add Step 3.7 Flash to your app at no cost — your users pay for their own AI usage directly, making it completely free for you as a developer.

What is the pricing for Step 3.7 Flash?
Step 3.7 Flash costs $0.2 per 1M input tokens and $1.15 per 1M output tokens.
Price per 1M tokens
Input$0.2
Output$1.15
Who created Step 3.7 Flash?

Step 3.7 Flash was created by StepFun and released on May 28, 2026.

What is the context window of Step 3.7 Flash?

Step 3.7 Flash supports a context window of 256K tokens. For reference, that is roughly equivalent to 512 pages of text.

What is the max output length of Step 3.7 Flash?

Step 3.7 Flash can generate up to 256K tokens in a single response.

How does Step 3.7 Flash perform on benchmarks?

Step 3.7 Flash scores 42.6 on the Artificial Analysis Intelligence Index, outperforming 87% of tracked models. On coding, it scores 37.1 (outperforms 83% of models).

Does it work with React / Vue / Vanilla JS / Node / etc.?

Yes — the Step 3.7 Flash API works with any JavaScript framework, Node.js, or plain HTML through Puter.js. Just include the library and start building. See the documentation for more details.

Get started with Puter.js

Add Step 3.7 Flash to your app without worrying about API keys or setup.

Read the Docs View Tutorials