Step-3.5-Flash (Reasoning)

by StepFun

Step-3.5-Flash (Reasoning) is a reasoning model from StepFun, released on February 2, 2026. It has a 66K-token context window and can generate up to 8K output tokens. API pricing is $0.1 per 1M input tokens and $0.4 per 1M output tokens.

Step-3.5-Flash is StepFun's fast, cost-effective text model optimized for quick inference. Built on their Step3 architecture, it offers strong performance across text tasks with low latency and efficient token usage, ideal for production workloads requiring speed and cost efficiency.

Key specs

ProviderStepFun
Release date2026-02-02
Licenseopen source
Context window66K tokens
Max output8K tokens
Input price$0.1 / 1M tokens
Output price$0.4 / 1M tokens
Intelligence Score37.1
Coding index20.2

Quick answers

What is the context window of Step-3.5-Flash (Reasoning)?

Step-3.5-Flash (Reasoning) has a context window of 66K tokens, with a maximum output of 8K tokens per response.

How much does Step-3.5-Flash (Reasoning) cost?

Step-3.5-Flash (Reasoning) costs $0.1 per 1M input tokens and $0.4 per 1M output tokens through the API.

Is Step-3.5-Flash (Reasoning) open source?

Yes. Step-3.5-Flash (Reasoning) is an open model released under the open source license.

When was Step-3.5-Flash (Reasoning) released?

StepFun released Step-3.5-Flash (Reasoning) on February 2, 2026.

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