StepFun: Step 3.5 Flash

Public pricingIntelligence 79/100Large memoryDeep thinkingTool use

StepFun: Step 3.5 Flash is a text model for general chat, analysis, and production use. It combines low latency and efficient inference and open-source flexibility with a 262K tokens context window and a low-cost profile. Use it for general chat, analysis, and production workloads when latency, cost, and throughput matters.

Input

$0.10/1M

Output

$0.30/1M

Cached

$0.01/1M

Batch

$0.07/1M

Calculate your Step 3.5 Flash bill.

Set your workload — see cost at your exact volume.

What would Step 3.5 Flash cost you?

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1,00010,00050,000250,0001M10M

Technical specifications

Step 3.5 Flash at a glance.

Memory

262,144

tokens

Max reply

65,536

tokens

Memory tier

Large

an entire book or large codebase

Tokenizer

—

Released

Jan 2026

Training cutoff

Oct 2025

Availability

Public pricing

Status

active

Benchmarks

Quality benchmarks

Independent evaluations from public leaderboards. Higher is better.

  • livecodebench

    86.4

  • aa_intelligence_index

    38

What it can do

Capabilities & limits.

  • Understands images
  • Deep step-by-step thinking
  • Uses tools / calls functions
  • Strict JSON output
  • Streams replies
  • Fine-tunable on your data

When to pick Step 3.5 Flash

  • Multi-step reasoning, research agents, or hard math.
  • Agentic workflows that call tools or APIs.
  • Long documents, full codebases, or extensive chat histories.
  • High-volume workloads where unit cost matters.

When to look elsewhere

  • Your workload involves images — pick a vision-capable model instead.

Alternatives

Similar models to compare.

FAQ

Step 3.5 Flash — the questions we see most.

Pricing, capabilities, alternatives — generated from the same data that powers the calculator above.

Get instant answers from our AI agent

At a typical workload of 50,000 conversations a month with 1,500-token prompts and 800-token replies, Step 3.5 Flash costs roughly $20 per month. Input is $0.10 /1M tokens and output is $0.30 /1M tokens.
Step 3.5 Flash has a 262,144-token context window (large memory — an entire book or large codebase). That means you can fit about 49,152 words of input and history in a single call.
Beyond text generation, Step 3.5 Flash supports deep step-by-step reasoning, calling functions / tools, strict JSON output, fine-tuning on your own data. It streams replies by default.
Step 3.5 Flash was released in January 2026, with training data cut off around October 2025.
Models in a similar class include Seed-2.0-Mini, Gemini 2.0 Flash, Gemini 2.5 Flash Lite. The "Similar models" section below this FAQ links into each.

Still unsure?

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