StepFun: Step 3.5 Flash

Other

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Paid

Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token. It is a reasoning model that is incredibly speed efficient even at long contexts.

Parameters

Context Window

256,000

tokens

Input Price

$0.1

per 1M tokens

Output Price

$0.3

per 1M tokens

Capabilities

Model capabilities and supported modalities

Performance

Reasoning

Excellent reasoning capabilities with strong logical analysis

Math

Coding

Knowledge

Modalities

Input Modalities

text

Output Modalities

text

LLM Price Calculator

Calculate the cost of using this model

Input Tokens (0.00000010/token)$0.000150

Output Tokens (0.00000030/token)$0.000900

Common Scenarios:

Input Cost:$0.000150

Output Cost:$0.000900

Total Cost:$0.001050

Estimated usage: 4,500 tokens

Monthly Cost Estimator

Based on different usage levels

Light Usage

$0.0040

~10 requests

Moderate Usage

$0.0400

~100 requests

Heavy Usage

$0.4000

~1000 requests

Enterprise

$4.0000

~10,000 requests

Note: Estimates based on current token count settings per request.

Last Updated: 2026/02/14