Grok 4.20 (Reasoning) API
About
Build advanced reasoning agents with Grok 4.20 (Reasoning), 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 4.20 (Reasoning) via the Impossibl API with up to 30K output tokens.
Capabilities
Input Modalities
textimagepdf
Output Modalities
text
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
Caching (per 1M tokens)
Read
$0.20
Frequently Asked Questions
Grok 4.20 (Reasoning) by Impossibl costs $1.25 per 1M input tokens and $2.50 per 1M output tokens. Cached reads cost $0.20 per 1M tokens.
Model Details
ID
xai/grok-4.20-0309-reasoning
Provider
ImpossiblFamily
grok
Release Date
Mar 9, 2026
Knowledge Cutoff
N/A
API Integration
NPM Package
@ai-sdk/openai-compatible
Environment Variables
IMPOSSIBL_API_KEY
API Base URL
https://api.impossibl.com/v1