Models/StepFun/Step 3.5 Flash

Step 3.5 Flash

Name: Step 3.5 Flash API access
Brand: StepFun

StepFun · Open weights · Released Jan 29, 2026 · stepfun/step-3.5-flash

Compare Estimate cost

262K contextToolsReasoningOpen weights

Available from 1 providerUSD / MTOK · VERIFIED 13 MINUTES AGO

EST. MONTHLY COSTclick a row for detail · click headers to sort

PROVIDER	INPUT	OUTPUT	CACHE	CONTEXT	QUANT	TTFT	TPS	UPTIME
SiliconFlow	$0.10	$0.30	—	262K	fp8	1.7s	81 tok/s	100.0%

TTFT/TPS: median (P50) over trailing 72h · chat10k profile (~10K in / 200 out) · measured via OpenRouter routing · methodology v1.1 · measured 44 hours ago

About

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....

Specifications

Context window262,144

Max output65,536

Modalities intext

Modalities outtext

LicenseOpen weights

ReleasedJan 29, 2026

TokenizerOther

WeightsHugging Face ↗

Open weights

Hugging Facestepfun-ai/Step-3.5-Flash ↗

Downloads160.3K

Likes833

Licenseapache-2.0

safetensors

Step 3.7 Flash$0.20 / $1.15

Embed badge

[![Step 3.5 Flash](https://modelindex.ai/badge/stepfun/step-3.5-flash)](https://modelindex.ai/models/stepfun/step-3.5-flash)

Sources

OpenRouter API13 minutes ago

AGGREGATOR

Hugging Face13 minutes ago

COMMUNITY

ModelIndex benchmarks44 hours ago

MEASURED

Verified 13 minutes ago · list prices, not negotiated rates.