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Step 3.7 Flash

StepFunReleased May 28, 2026

Step 3.7 Flash is StepFun's latest high-efficiency multimodal Mixture-of-Experts model. It pairs a 196B-parameter language backbone with a vision encoder for native image and video understanding, activating roughly 11B parameters...

Try in playground
Context window
256K tokens
Max output
256K tokens
Input
text, image, video
Output
text
Tokenizer
Other
Released
May 28, 2026
Reasoning
always on

Pricing

Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.

Per 1M tokensProvider+ 3% feeYou pay
Input$0.200$0.0060$0.206
Output$1.15$0.034$1.18
Cache read$0.040$0.0012$0.041

Benchmarks

Artificial Analysis

Intelligence index
29.7
Coding index
37.3
Agentic index
21.5

Design Arena

CategoryEloWin rateRank
3Dmodels119743.2%#46
ASCII artmodels122751.5%#13
Codemodels121745.7%#44
Data vizmodels121246.7%#41
Game devmodels120741.6%#43
SVGmodels112239.8%#49
UI componentsmodels121244.6%#44
Websitesmodels122547.1%#43

Head-to-head preference voting. How we filter and rank

Supported parameters

  • frequency_penalty
  • include_reasoning
  • logit_bias
  • logprobs
  • max_tokens
  • min_p
  • presence_penalty
  • reasoning
  • repetition_penalty
  • response_format
  • seed
  • stop
  • structured_outputs
  • temperature
  • tool_choice
  • tools
  • top_k
  • top_logprobs
  • top_p

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model stepfun/step-3.7-flash.

Code sample language
curl https://api.openkey.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "stepfun/step-3.7-flash",
    "messages": [{"role": "user", "content": "Hello"}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.openkey.ai/v1",
    api_key=os.environ["OPENKEY_API_KEY"],
)

completion = client.chat.completions.create(
    model="stepfun/step-3.7-flash",
    messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.openkey.ai/v1",
  apiKey: process.env.OPENKEY_API_KEY,
});

const completion = await client.chat.completions.create({
  model: "stepfun/step-3.7-flash",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does Step 3.7 Flash cost via API?
Through OpenKey, Step 3.7 Flash costs $0.206 per 1M input tokens and $1.18 per 1M output tokens. That is the provider price ($0.200 / $1.15) plus a flat 3% fee — nothing else.
What is Step 3.7 Flash's context window?
Step 3.7 Flash accepts up to 256K tokens of context and returns up to 256K tokens per request.
Is Step 3.7 Flash OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "stepfun/step-3.7-flash" using any OpenAI SDK — only the base URL and API key change.
What inputs does Step 3.7 Flash support?
Step 3.7 Flash accepts text, image, video input and produces text output.

More from StepFun

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