xAI: Grok 4 Fast (free) vs OpenAI o4-mini
Compare xAI: Grok 4 Fast (free) by xAI against OpenAI o4-mini by OpenAI, tested across 35 shared challenges. Updated April 2026.
Which is better, xAI: Grok 4 Fast (free) or OpenAI o4-mini?
xAI: Grok 4 Fast (free) and OpenAI o4-mini are both competitive models. xAI: Grok 4 Fast (free) costs $0/M input tokens vs $1.1/M for OpenAI o4-mini. Compare their real outputs side by side below.
Key Differences Between xAI: Grok 4 Fast (free) and OpenAI o4-mini
xAI: Grok 4 Fast (free) is made by xai while OpenAI o4-mini is from openai. On pricing, xAI: Grok 4 Fast (free) costs $0/M input tokens vs $1.1/M for OpenAI o4-mini.
No community votes yet. On paper, xAI: Grok 4 Fast (free) has the edge — bigger model tier, newer, bigger context window.
Style Comparison
xAI: Grok 4 Fast (free) uses 138.0x more bold
vsAsk them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
