Grok-4.1-Fast-Reasoning API
About
Build advanced reasoning agents with Grok-4.1-Fast-Reasoning, 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 Grok-4.1-Fast-Reasoning via the Poe API with up to 30K output tokens.
Capabilities
Input Modalities
textimage
Output Modalities
text
Reasoning
Yes
Structured Output
No
Tool Use
Yes
WeightsClosed
Temperature
Fixed
Attachment
Supported
Limits
Context Window
2.0M
Tokens
Input Limit
2.0M
Tokens
Max Output
30K
Tokens
Pricing
Standard (per 1M tokens)
Input
Free
Output
Free
Frequently Asked Questions
Grok-4.1-Fast-Reasoning by Poe costs Free per 1M input tokens and Free per 1M output tokens.
Model Details
API Integration
NPM Package
@ai-sdk/openai-compatible
Environment Variables
POE_API_KEY
API Base URL
https://api.poe.com/v1