Crux privacy policy
Last updated: October 8, 2026
Crux is a browser extension that shows x.com in a different layout. It has no server and no account. Nothing it reads or stores is sent to its developer.
What Crux reads
While you use x.com, Crux reads the posts, notifications, trends, and profile pages that x.com shows in your browser, the same pages you could scroll yourself. It reads them only on x.com.
What Crux stores
Crux stores its settings and the lists it built (posts, your recent posts used to match your voice, and timings) in your browser's extension storage. They stay on your device. Removing the extension deletes them.
What Crux sends, and where
Crux sends nothing unless you add an API key for an AI provider. You choose the provider: OpenAI, Anthropic, or OpenRouter. With a key, Crux sends that provider the text of posts it read, your recent posts, and the About you and Topics text you typed, so the model can write the Brief, pick posts for Hot, and draft replies and post ideas. Requests go straight from your browser to the provider, with your key. The provider's own privacy policy covers what it does with them.
Your API key is stored in your browser's extension storage and sent only to the provider it belongs to.
What Crux does on x.com
Crux likes, reposts, or opens a reply or quote box only when you press the button for it. It never posts on its own: you press Post in x.com's own composer.