Grok 4 Fast (Reasoning) API
About
Build advanced reasoning agents with Grok 4 Fast (Reasoning), a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers cost-effective pricing at $0.20/1M input and $0.50/1M output tokens, native tool calling support. Access Grok 4 Fast (Reasoning) via the Azure Cognitive Services API with up to 30K output tokens.
Capabilities
Input Modalities
textimage
Output Modalities
text
Reasoning
Yes
Limits
Context Window
2.0M
Tokens
Input Limit
2.0M
Tokens
Max Output
30K
Tokens
Pricing
Standard (per 1M tokens)
Input
$0.20
Output
$0.50
Caching (per 1M tokens)
Read
$0.05
Frequently Asked Questions
Grok 4 Fast (Reasoning) by Azure Cognitive Services costs $0.20 per 1M input tokens and $0.50 per 1M output tokens. Cached reads cost $0.05 per 1M tokens.
Model Details
ID
grok-4-fast-reasoning
Provider
Azure Cognitive ServicesFamily
grok
Release Date
Sep 19, 2025
Knowledge Cutoff
Jul 1, 2025
API Integration
NPM Package
@ai-sdk/azure
Environment Variables
AZURE_COGNITIVE_SERVICES_RESOURCE_NAME
AZURE_COGNITIVE_SERVICES_API_KEY