Neura Market
Lex logo

Lex

Free

A word processor with artificial intelligence baked in, so you can write faster.

FreeFree tier
Inputs: textOutputs: text
Type
Open Source
Company
Lex, Inc
Visit Website GitHub (40 stars)

About Lex

Lex is a collaborative word processor designed for serious writing, integrating powerful AI editing tools directly into the document. It offers a minimalist interface that helps writers focus, with AI capabilities to provide feedback, brainstorm ideas, rewrite text, generate title ideas, and suggest line-level improvements. Users can collaborate in real-time, leave comments, manage versions, and share read-only links. Lex supports integration with Kit (formerly ConvertKit), custom style guides, knowledge bases, and a prompt library. It is free to start, with a premium Pro plan that unlocks the largest AI models (e.g., GPT-4.1, Claude 4 Opus/Sonnet), early access to features, priority support, and an iOS app. Lex emphasizes privacy, does not train AI on user data, and uses enterprise APIs from OpenAI, Anthropic, and TogetherAI.

Key Features

AI Feedback: Get AI suggestions on drafts, brainstorm ideas, or rewrite text
Live Collaboration: Share a link and see each other typing in real time
Versions: Create manual save points or scrub through previous document versions
Comments: Polished comment system with keyboard shortcuts
Publishing: Send read-only links for readers
Commands: Handy AI shortcuts for finding words, generating ideas
Title Ideas: One-click AI generation of title suggestions
Checks: Get line-level suggestions highlighted in the document
Style Guides: Train Lex to draft and edit in your voice
Knowledge Bases: Give AI persistent background knowledge for personalized help

Pros & Cons

Pros
  • Minimalist interface designed to reduce distraction and improve focus
  • AI capabilities serve as a real-time editor to iterate faster
  • Free to start with no credit card required
  • Strong privacy protections: does not train AI on user data
  • Flexible AI model selection adapting to the best available LLMs
  • Robust collaboration features including live typing and comments
  • Version control with rewind and manual save points
Cons
  • Some advanced AI features (premium models) require a paid Pro subscription
  • Track Changes is not yet available (coming soon)
  • Free users have limits on Ask Lex messages, Checks, and custom prompts
  • No native desktop app so far (only web and mobile web)

Best For

Academic papers and journal submissionsCustomer-facing copy and marketing materialsImportant emails that require careful editingFiction writing needing a second pair of eyesNewsletter writing (with Kit integration)Any writing that goes through an edit process

FAQ

What is the benefit of upgrading to Lex Pro?
Access to the biggest and best AI models (like GPT-4.1 and Claude 4 Opus & Sonnet), early access to new features including an iOS app, and priority support via email. Pro also enables unlimited group use of Lex folders with Lex Teams.
Is Lex secure and private?
Yes. All data is privately and securely hosted on Lex's own database. They have strict policies about team access and will always ask for permission. Lex uses enterprise APIs from OpenAI, Anthropic, and TogetherAI, which provide stronger privacy protections.
Is my writing being used to train the AI?
No. Lex does not train language models on user data. It uses models through enterprise APIs that offer additional privacy. If Lex ever does train models, they will explicitly inform users via email and allow opt-out.
Can I use Lex with my team?
Yes, sharing and collaborating on documents is free. For heavy collaboration, you can add Lex Teams to a Pro subscription for unlimited group use of folders.
What kind of writing is Lex designed for?
Anything that goes through an edit process: academic papers, customer-facing copy, important emails, fiction writing, and any document that benefits from a second pair of eyes.
Do you offer refunds?
Yes. If you don't love Lex after a month, you can reach out for a refund.