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Step 3.7 Flash

Step 3.7 Flash is StepFun's flagship multimodal reasoning model, a sparse MoE with 11B active parameters and native image and video understanding. It supports a context window of 256K tokens and a max output of 256K tokens per request.

Implicit CachingReasoningTool UseVision (Image)
index.ts
import { streamText } from 'ai'


const result = streamText({
  model: 'stepfun/step-3.7-flash',
  prompt: 'Why is the sky blue?'
})
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Frequently Asked Questions

  • What architecture does Step 3.7 Flash use?

    Step 3.7 Flash pairs a sparse mixture-of-experts language backbone with a dedicated vision encoder, totaling roughly 198B parameters with 11B active per token. See https://platform.stepfun.ai/docs/en/guides/models/step-3.7-flash for details.

  • What visual inputs can Step 3.7 Flash understand?

    Step 3.7 Flash natively understands images and video, including product UIs, documents, charts, spreadsheets, and natural scenes. A built-in Python tool lets Step 3.7 Flash crop, zoom, and annotate images during a task.

  • How does Step 3.7 Flash differ from step-3.5-flash?

    Step 3.7 Flash adds a vision encoder for native image and video understanding, which step-3.5-flash lacks. Step 3.7 Flash also improves agentic coding, gaining about five points on SWE-Bench Pro and six points on Terminal-Bench 2.1 over its predecessor.

  • What is the context window for Step 3.7 Flash?

    Step 3.7 Flash supports a context window of 256K tokens and a max output of 256K tokens per request.

  • How well does Step 3.7 Flash perform on benchmarks?

    Step 3.7 Flash scores 76.5% on SWE-Bench Verified, 56.3% on SWE-Bench Pro, 59.5% on Terminal-Bench 2.1, and 75.82% on BrowseComp in StepFun's published evaluations. Vision results include 95.29% on V* with Python tooling and 89.13% on HR-Bench 4K.

  • How do I call Step 3.7 Flash through AI Gateway?

    Use the model identifier stepfun/step-3.7-flash with the AI SDK, the Chat Completions API, the Responses API, the Messages API, or another supported API format. You authenticate with an AI Gateway API key, and no StepFun account is needed.

  • Does AI Gateway support Zero Data Retention for Step 3.7 Flash?

    Zero Data Retention is not currently available for this model. Zero Data Retention is offered on a per-provider basis. See https://vercel.com/docs/ai-gateway/capabilities/zdr for details.