Lex
AI-native writing editor for long-form prose
About
Lex is a minimalist web editor built around AI rather than bolted onto it: type +++ to continue a draft, ask for improvements, or open an AI critique panel that reviews your writing from a configurable point of view. Style guides and knowledge bases train the assistant on your voice and project context, while rewind and named versions let you test alternate wording safely. It routes requests through enterprise APIs from OpenAI, Anthropic, and TogetherAI (premium models like GPT-4.1, GPT-5, and Claude Opus class on Pro) and does not train on your documents. Third-party sources disagree on Pro pricing ($12–$18/mo; one tracker cites $14.99/mo annual from lex.page/pricing) — check the vendor. Free covers collaborative docs with basic models and AI usage limits. Track Changes is still listed as coming soon, and the iOS app is a Pro benefit.
What it can do
- In-editor AI continuation, rewriting, and critique
- Style guides and knowledge bases for voice training
- Rewind and named draft versions
- Real-time collaboration via shared links
- Premium frontier models on Pro
- Markdown export
Setup
Sign up at lex.page and start a new document. Type +++ to summon AI commands, or use Ask Lex for feedback and checks as you write.
Prerequisites
Web browser.
Use cases
Works with
Trust score — 7/10
Scored 7/10 (verified tier, metrics-v1). Evidence: AI-native editor (+++ commands, Ask Lex, critique panel, style guides, rewind/versions, collaboration) documented across aitools.fyi, skillpack research notes, and Fast Company hands-on.; Enterprise-API routing (OpenAI/Anthropic/TogetherAI) and premium model list from aitools.fyi's pricing-page read; no-training-on-docs claim is vendor-stated.; Pro pricing conflicts across sources ($12-$18/mo; $14.99/mo annual cited from lex.page/pricing) — disclosed as range with vendor check advised..
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.