stepfun · Open weights

Step 3.7 Flash Thinking

Added May 29, 2026Open weights

Step 3.7 Flash Thinking is StepFun's high-efficiency multimodal MoE model with visible reasoning enabled for deeper agentic coding, long-context reasoning, tool use, and native image/video understanding. ⚠️ Note: This model routes through StepFun, so privacy and logging guarantees may be limited.

Reasoning
Tools
Vision
Structured output
Video input

Input: Text, Images, Video
Output: Text
Reasoning effort: none · low · medium · high
Discovery tier: Open weights

Pricing

USD per 1M tokens

Input: $0.20
Output: $1.15
Cache read: $0.04

Reference prices as published by the model provider. API example

Specifications

Context window: 262.1K
Max output: 256K
Average output (7 days): 7.1K tokens; Longer than 99% of 465 models

Side by side

Compare models

Put Step 3.7 Flash Thinking next to up to three other models. The comparison stays in the link, so you can share it.

TryGLM 5.3 Flash Uncensored Qwen3.6 35B A3B TEE Ministral 14B All 3

Public evaluations

Benchmarks

There are no public benchmark results for Step 3.7 Flash Thinking yet.

Live routing data

Performance and reliability

Recent averages across requests routed for this model. Your own speed depends on prompt length, reasoning effort and load.

Prompt cache hits: 0.0%; About $0.20 per 1M input tokens with caching
Request success (24h): 100.0%

Cache hits are the share of input tokens recently served from a prompt cache across all requests. They are not a forecast of your own hit rate.

Developers

Use it through the API

Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.

Read the quickstart

curl https://www.noumen.xyz/api/v1/chat/completions \
  -H "Authorization: Bearer $NOUMEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "stepfun/step-3.7-flash:thinking",
    "reasoning_effort": "medium",
    "messages": [{ "role": "user", "content": "Explain this stack trace." }]
  }'

import os
from openai import OpenAI

client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
    model="stepfun/step-3.7-flash:thinking",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

stepfun

Other stepfun models, starting with the same family.