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xAI: Grok 4 Fast

x-ai/grok-4-fast
Sep 19, 20252M context30K max output$0.20/M in · $0.50/M outReasoningDeprecates 2026-05-15

Upcoming deprecation

This model will be deprecated on 2026-05-15. Please plan to migrate to an alternative model before this date.

Description

Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model on xAI's news post.

Reasoning can be enabled/disabled using the reasoning enabled parameter in the API. Learn more in our docs

Specifications

Provider
x-ai
Context Length
2M
Max Output
30K
Modality
Intextimage
Outtext

Pricing

TypePrice / 1M tokens
Input$0.20
Output$0.50
Cache Read$0.05
Web Search$0.0050 / call

Quick Start

curl https://api.ominigate.ai/v1/chat/completions \
  -H "Authorization: Bearer sk-omg-your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "x-ai/grok-4-fast",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'