StepFun: Step 3.5 Flash
stepfun/step-3.5-flash
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.
Model specifications
- Input
- text
- Output
- text
- Context
- 256,000 tokens
- Max output
- 256,000 tokens
- Input price
- $0.1 / 1M tokens
- Output price
- $0.3 / 1M tokens
- Released
- 2026-02-26
Capabilities
- Streaming
- Playground
Provider pricing, discounts and data privacy
Compare effective provider prices, published discounts, regions, retention policies, training use, compliance, and privacy links by service tier.
Standard service tier
1 available provider · tier input average $0.1 / 1M tokens · tier output average $0.3 / 1M tokens
SiliconFlow
Tier: Standard · Region: SG
Pricing
- Input
- $0.1 / 1M tokens
- Output
- $0.3 / 1M tokens
No provider discount is currently published.
Data privacy and compliance
- Region
- SG
- Zero data retention
- No
- Data retention
- Unknown retention
- Used for training
- No
- Data collection
- Moderated
- No
- GDPR compliant
- No
- HIPAA compliant
- No
- SOC 2 certified
- No
- BYOK supported
- No
Privacy policy · Terms · Official website · Documentation · Support
Frequently asked questions
- What is StepFun: Step 3.5 Flash?
- 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.
- How much does StepFun: Step 3.5 Flash cost?
- Input costs start at $0.1 / 1M tokens and output costs start at $0.3 / 1M tokens. Provider-level prices vary by service tier.
- What is the context length of StepFun: Step 3.5 Flash?
- StepFun: Step 3.5 Flash supports a 256,000 token context window and up to 256,000 output tokens.
- What capabilities does StepFun: Step 3.5 Flash support?
- StepFun: Step 3.5 Flash supports Streaming, Playground.
- Which providers offer StepFun: Step 3.5 Flash?
- StepFun: Step 3.5 Flash is available from SiliconFlow.
- How do providers handle data privacy for StepFun: Step 3.5 Flash?
- 1 of 1 providers report that customer data is not used for training, and 0 offer zero-data-retention routing. Retention, compliance, and privacy-policy links are listed per provider.