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StepFun: Step 3.5 Flash API Pricing

StepFun: Step 3.5 Flash is an API model from stepfun. It costs $0.1 per 1M input tokens and $0.3 per 1M output tokens. Its context window is 262,144 tokens with up to 65,536 output tokens. A workload of 10M input + 2M output tokens costs about $1.6 per month.

Input

$0.1

per 1M tokens

Output

$0.3

per 1M tokens

Cached input

—

per 1M tokens

Context window

262K

262,144 tokens

Blended (80/20)

$0.14

per 1M tokens

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....

How much does StepFun: Step 3.5 Flash cost for a real workload?

At 10M input + 2M output tokens per month, StepFun: Step 3.5 Flash costs about $1.6 ($1 input + $0.6 output). Try your own volumes in the cost calculator.

What are cheaper alternatives to StepFun: Step 3.5 Flash?

Qwen: Qwen3 30B A3B Instruct 2507 — $0.09 in / $0.3 out per 1M
Meta: Llama 3.2 3B Instruct — $0.0509 in / $0.335 out per 1M
Mistral: Mistral Small 4 (batch) — $0.075 in / $0.3 out per 1M
ByteDance Seed: Seed 1.6 Flash — $0.075 in / $0.3 out per 1M
OpenAI: gpt-oss-safeguard-20b — $0.075 in / $0.3 out per 1M
OpenAI: GPT-4o-mini (batch) — $0.075 in / $0.3 out per 1M

Where to run StepFun: Step 3.5 Flash

AI/ML API: one API key for 400+ models, including most models tracked here · Novita AI: pay-as-you-go APIs for open models (DeepSeek, Qwen, Llama and more) plus GPU cloud. Prices there follow each platform's own catalog and can differ from the list prices tracked here.

Run it on AI/ML API →Run it on Novita AI →

Disclosure: links to these platforms may be affiliate links — if you sign up or buy through them, LLMPrices may earn a commission at no extra cost to you.

Compare StepFun: Step 3.5 Flash with other models

StepFun: Step 3.5 Flash vs StepFun: Step 3.7 FlashStepFun: Step 3.5 Flash vs StepFun: Step 5 Preview

Frequently asked questions

How much does StepFun: Step 3.5 Flash cost?

StepFun: Step 3.5 Flash costs $0.1 per 1M input tokens and $0.3 per 1M output tokens (list price, snapshot October 22, 2026). At 10M input + 2M output tokens per month that is about $1.6.

What is the context window of StepFun: Step 3.5 Flash?

StepFun: Step 3.5 Flash has a context window of 262,144 tokens and can return up to 65,536 output tokens per response.

What are cheaper alternatives to StepFun: Step 3.5 Flash?

Cheaper models include Qwen: Qwen3 30B A3B Instruct 2507 ($0.09 in / $0.3 out), Meta: Llama 3.2 3B Instruct ($0.0509 in / $0.335 out), Mistral: Mistral Small 4 (batch) ($0.075 in / $0.3 out). See the full list on this page.

Is StepFun: Step 3.5 Flash free to use?

No. StepFun: Step 3.5 Flash is a paid model at $0.1 input / $0.3 output per 1M tokens. 21 free models are listed on the free models page.

Provider: stepfun · Model ID: stepfun/step-3.5-flash · Modality: text->text · Price snapshot October 22, 2026, refreshed daily. How we collect prices