Step 3.7 Flash
About this model
Step 3.7 Flash is an AI model from StepFun, made available through the API on May 28, 2026. It can read up to 262,144 tokens in one request, roughly 492 pages of text, and write up to 230,400 tokens in a single answer. Besides text, it accepts images and video as input.
Through the API it costs $0.20 per million input tokens and $1.15 per million output tokens. Its pricing sits in the middle of the market.
It supports extended reasoning: it can "think" step by step before answering, which helps on maths, code and complex questions. It can call tools and functions, so developers can connect it to search, databases or other software. Its weights are openly published (stepfun-ai/Step-3.7-Flash), so it can also be downloaded and run on your own hardware.
Quality scores
Rankings →Not rated yet. Independent test results usually appear a few weeks after a model is released.
Where to use it
Companies that serve this model through an API: 3. Prices per million tokens, cheapest first.
| Provider | Inputi | Outputi | Contexti | Uptime (24 h)i |
|---|---|---|---|---|
DeepInfraCheapest | $0.16 | $0.92 | 256K | 99.9% |
Novitafp8 | $0.20 | $1.15 | 256K | 99.6% |
StepFunOfficialfp8 | $0.20 | $1.15 | 256K | 99.7% |
Availability and prices come from OpenRouter’s public API and are refreshed daily. Uptime is the share of successful requests over the last 24 hours. Some providers run a compressed version of open models (fp8, int4), which is cheaper but can be slightly less accurate.
Use it in your code
Call Step 3.7 Flash through OpenRouter’s OpenAI-compatible API: create a key on openrouter.ai, then run one of these examples.
curl https://openrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $OPENROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "stepfun/step-3.7-flash", "messages": [{"role": "user", "content": "Hello! What can you do?"}]}'import os
from openai import OpenAI
client = OpenAI(base_url="https://openrouter.ai/api/v1", api_key=os.environ["OPENROUTER_API_KEY"])
reply = client.chat.completions.create(
model="stepfun/step-3.7-flash",
messages=[{"role": "user", "content": "Hello! What can you do?"}],
)
print(reply.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://openrouter.ai/api/v1", apiKey: process.env.OPENROUTER_API_KEY });
const reply = await client.chat.completions.create({
model: "stepfun/step-3.7-flash",
messages: [{ role: "user", content: "Hello! What can you do?" }],
});
console.log(reply.choices[0].message.content);The same code works with every model on this site: only the model ID changes. Many labs also offer their own API and SDK.
What it costs in practice
- 1,000 chat replies$0.445
- Summarise a 100-page document$0.011
- An app with 10,000 requests a day for a month$198
Similar-priced alternatives
| Model | Inputi | Outputi | Contexti | |
|---|---|---|---|---|
GPT-5.6 Luna ProOpenAI | $0.20 | $1.20 | 1.1M | Compare with ⇄ |
| $0.20 | $0.20 | 128K | Compare with ⇄ | |
DeepSeek V4 Flash Vision ExpDeepSeek | $0.22 | $0.65 | 1M | Compare with ⇄ |
Perceptron Mk1.5Perceptron | $0.15 | $1.50 | 36K | Compare with ⇄ |
Qwen3.8 Omni FlashAlibaba Qwen | $0.15 | $0.47 | 1M | Compare with ⇄ |
GLM 5.3 FlashZ.ai (Zhipu) | $0.15 | $0.50 | 1M | Compare with ⇄ |
Frequently asked questions
- How much does Step 3.7 Flash cost?
- Step 3.7 Flash costs $0.20 per million input tokens and $1.15 per million output tokens through the API. For example, 1,000 chat replies of about 500 tokens in and 300 out cost around $0.445.
- What is the context window of Step 3.7 Flash?
- Step 3.7 Flash can read up to 262,144 tokens in one request, about 492 pages of text. It can write up to 230,400 tokens in a single answer.
- Is Step 3.7 Flash open source?
- Yes. Its weights are published (stepfun-ai/Step-3.7-Flash), so you can download it and run it on your own hardware, or use it through one of 3 API providers.
- Who makes Step 3.7 Flash?
- Step 3.7 Flash is made by StepFun. It became available through the API on May 28, 2026.
- Can Step 3.7 Flash read images?
- Yes. Besides text, it accepts images and video as input.
- What are the alternatives to Step 3.7 Flash?
- Models with a similar price from other companies include GPT-5.6 Luna Pro, Nemotron 3.5 Content Safety and DeepSeek V4 Flash Vision Exp. You can compare them side by side on this page.