Grok 4 Fast Thinking by NanoGPT — Specs, Pricing & Capabilities | whichllm

Model ID x-ai/grok-4-fast:thinking

Provider NanoGPT

Family grok

Status -

Knowledge Cutoff -

Release Date 2025-07-09

Input Modalities text, image

Output Modalities text

Context Window 2000000

Input Limit 2000000

Output Limit 131072

Tool Calling Yes

Reasoning Yes

Structured Output Yes

Temperature Control -

Open Weights No

Input Cost / 1M tokens $0.20

Output Cost / 1M tokens $0.50

Reasoning Cost / 1M tokens -

Cache Read Cost / 1M tokens -

Cache Write Cost / 1M tokens -