Lex is an AI-powered writing editor built for serious writers who want intelligent assistance without losing their own voice. It pairs a clean, distraction-free document editor with AI that stays out of the way until you ask for it: type +++ on a new line to open an inline prompt where you can request feedback, brainstorm ideas, rewrite a passage, expand a paragraph, or generate a title. Rather than acting as a ghostwriter, Lex is designed to behave like a thoughtful editor, offering critiques, catching weak arguments, and suggesting improvements while leaving the writing under your control. Pro subscribers get access to premium frontier models including GPT-4o and Anthropic's Claude family, while the free plan runs on lighter open models. Lex also includes grammar, spelling, and style checks, an AI chat that can answer questions about your document, shareable links for collaborative review, real-time collaboration, and version history that tracks changes over time. It runs in the browser with a focused, minimalist interface that keeps the emphasis on the words on the page.