StepFun: Step 3.5 Flash (free) API
About
Build advanced reasoning agents with StepFun: Step 3.5 Flash (free), a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers available completely free of charge, native tool calling support. Access StepFun: Step 3.5 Flash (free) via the Kilo Gateway API with up to 262K output tokens.
Capabilities
Input Modalities
text
Output Modalities
text
Reasoning
Yes
Structured Output
No
Tool Use
Yes
WeightsClosed
Limits
Context Window
262K
Tokens
Input Limit
262K
Tokens
Max Output
262K
Tokens
Pricing
Standard (per 1M tokens)
Input
Free
Output
Free
Frequently Asked Questions
StepFun: Step 3.5 Flash (free) by Kilo Gateway costs Free per 1M input tokens and Free per 1M output tokens.
Model Details
API Integration
NPM Package
@ai-sdk/openai-compatible
Environment Variables
KILO_API_KEY
API Base URL
https://api.kilo.ai/api/gateway