Grok 4.3 API
About
Build advanced reasoning agents with Grok 4.3, a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers cost-effective pricing at $1.25/1M input and $2.50/1M output tokens, native tool calling support. Access Grok 4.3 via the FastRouter API with up to 30K output tokens.
Capabilities
Input Modalities
textimagepdf
Output Modalities
text
Reasoning
Yes
Structured Output
Yes
Tool Use
Yes
WeightsClosed
Temperature
Adjustable
Attachment
Supported
Limits
Context Window
1.0M
Tokens
Input Limit
1.0M
Tokens
Max Output
30K
Tokens
Pricing
Standard (per 1M tokens)
Input
$1.25
Output
$2.50
Frequently Asked Questions
Grok 4.3 by FastRouter costs $1.25 per 1M input tokens and $2.50 per 1M output tokens.
Model Details
API Integration
NPM Package
@ai-sdk/openai-compatible
Environment Variables
FASTROUTER_API_KEY
API Base URL
https://go.fastrouter.ai/api/v1