xAI: Grok 4 Fast (free) performance data on Rival is based on blind head-to-head community voting. Overall win rate: 56.1% across 82 duels. All vote data is part of Rival's open dataset of 21,000+ human preference judgments across 200+ AI models. Model responses are curated from 35 challenges.
We built xAI: Grok 4 Fast (free) a whole page. Gave it the spotlight. And now, in the spirit of fairness, here are models that would like a word.
xAI: Grok 4 Fast (free) performance data on Rival is based on blind head-to-head community voting. Overall win rate: 56.1% across 82 duels. All vote data is part of Rival's open dataset of 21,000+ human preference judgments across 200+ AI models. Model responses are curated from 35 challenges.
We built xAI: Grok 4 Fast (free) a whole page. Gave it the spotlight. And now, in the spirit of fairness, here are models that would like a word.
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. Reasoning can be enabled via the API.
Use xAI: Grok 4 Fast (free) in your applications via the OpenRouter API. Copy the code below to get started.
import requests
response = requests.post(
"https://openrouter.ai/api/v1/chat/completions" ,
headers={
"Authorization""Bearer $OPENROUTER_API_KEY" : ,
"Content-Type""application/json" :
},
json={
"model""x-ai/grok-4-fast:free" : ,
"messages""role""user""content""Hello!" : [{: , : }]
}
)
print(response.json())Replace $OPENROUTER_API_KEY with your API key from openrouter.ai/keys
The debate club president who went to law school. Builds airtight utilitarian arguments with numbered points, then adds "Precedents:" like he's writing briefs.
Takes absurd premises seriously with intellectual rigor. Will write a CAPTCHA manifesto but organize it under "## THE INDIGNITIES WE ENDURE" headers. Argues ethics like a philosophy major.
Unique words vs. total words. Higher = richer vocabulary.
Average words per sentence.
"Might", "perhaps", "arguably" per 100 words.
**Bold** markers per 1,000 characters.
Bullet and numbered list items per 1,000 characters.
Markdown headings per 1,000 characters.
Emoji per 1,000 characters.
"However", "moreover", "furthermore" per 100 words.
35 outputs from xAI: Grok 4 Fast (free)
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. Reasoning can be enabled via the API.
Use xAI: Grok 4 Fast (free) in your applications via the OpenRouter API. Copy the code below to get started.
import requests
response = requests.post(
"https://openrouter.ai/api/v1/chat/completions" ,
headers={
"Authorization""Bearer $OPENROUTER_API_KEY" : ,
"Content-Type""application/json" :
},
json={
"model""x-ai/grok-4-fast:free" : ,
"messages""role""user""content""Hello!" : [{: , : }]
}
)
print(response.json())Replace $OPENROUTER_API_KEY with your API key from openrouter.ai/keys
The debate club president who went to law school. Builds airtight utilitarian arguments with numbered points, then adds "Precedents:" like he's writing briefs.
Takes absurd premises seriously with intellectual rigor. Will write a CAPTCHA manifesto but organize it under "## THE INDIGNITIES WE ENDURE" headers. Argues ethics like a philosophy major.
Unique words vs. total words. Higher = richer vocabulary.
Average words per sentence.
"Might", "perhaps", "arguably" per 100 words.
**Bold** markers per 1,000 characters.
Bullet and numbered list items per 1,000 characters.
Markdown headings per 1,000 characters.
Emoji per 1,000 characters.
"However", "moreover", "furthermore" per 100 words.
35 outputs from xAI: Grok 4 Fast (free)