grok-4-fast-non-reasoning vs gpt-5-nano

xAI grok-4-fast-non-reasoningOpenAI gpt-5-nano
VendorxAIOpenAI
Context window2,097,152400,000
Max output30,000128,000
ReasoningNoYes
Tool callingYesYes
File inputYesYes
Inputtext, imagetext, image
Outputtexttext
Released2025-08-272025-08-07