Lex

Free plan APIiPhoneWeb

What Lex is

Lex is a collaborative document editor with AI tools for developing and revising writing. It can provide feedback on drafts, help with brainstorming and rewrites, respond to commands and suggest titles with one click. Documents can be shared for live collaboration, comments or read-only publishing; collaborators can join from a link without downloading an app. Teams can create reusable prompts and shared context tags to give the AI background about their voice, goals and past work. The Kit integration uses recent and high-performing newsletters to shape drafting prompts and subject-line ideas, and can send finished writing to Kit. Lex also offers a developer API. It is intended for writing that benefits from editing, including academic papers, customer-facing copy, important emails and fiction. Lex is available on the web and iOS, with mobile web collaboration and iOS access included in Pro. Free accounts are limited to 30 Ask Lex messages per day, five saved prompt runs per month and a low daily AI processing budget. Lex says it does not train models on customer content without explicit written permission.

Who it suits

Lex suits people writing work that needs editing or revision, from academic papers and customer-facing copy to important emails and fiction. Shared prompts and context tags may help teams align AI assistance with their voice and goals.

What it does well

Live collaboration, comments and read-only publishing.
Link-based collaborators need not download an app.
Custom prompts and shared context tags.
Kit integration supports drafting prompts and subject lines.

What to know first

Free accounts have daily and monthly AI-use limits.
No desktop app or browser extension.
Pro price is not displayed on the listed pricing page.

Limits

Free accounts are limited to 30 Ask Lex messages per day, five saved prompt runs per month and a low daily AI processing budget. Pro pricing is not displayed on the listed pricing page.

Plans

Plan	Billed and limits	Price
Free	30 Ask Lex messages per day · 5 saved-prompt runs per month · low daily AI budget	Free
Lex Pro annual	annual; equivalent to $14.99/month; price announced effective July 18, 2025 · premium AI models · early feature access · iOS app · priority email support	$179.88 a year
Lex Pro monthly	monthly; price announced effective July 18, 2025 · premium AI models · early feature access · iOS app · priority email support	$24.99 a month
Lex Pro	Monthly version mentioned; price not displayed on the opened pricing page. · Access to premium AI models · early access to features and the iOS app · priority email support	On request

As lex.page lists them, read 21 Oct 2026. The maker's own page has the final word.

Getting started

Open Lex in a web browser
Create a free account or choose Pro
Share a document link for collaboration
Create reusable prompts and context tags
Connect Kit for newsletter-based drafting
Use the iOS app with Pro or access the developer API

Verdict

Lex brings AI writing assistance and document collaboration together, with custom context and a Kit integration. Consider the free-account limits and the undisplayed Pro price when deciding whether its tools fit your writing needs.

Questions

Does Lex have a free plan?

Yes. Lex offers a free plan with daily and monthly AI-use limits.

What does Lex Pro include?

Pro includes premium AI models, early access to features and the iOS app, plus priority email support. The listed pricing page does not display a price.

Which platforms does Lex support?

Lex is available on the web and iOS and offers an API. It has no desktop app or browser extension.

Can people collaborate without installing Lex?

Yes. Documents can be shared for live collaboration, comments or read-only publishing, and collaborators can join from a link without downloading an app.

Does Lex integrate with Kit?

Yes. Kit can analyze recent and high-performing newsletters to create custom prompts, suggest subject lines and receive finished writing.

Does Lex train AI models on customer content?

Lex says it does not train AI models on customer content without explicit written permission.

Facts from Lex's own pages

AI feedback: Users can ask AI for draft feedback, brainstorming and rewrites. · lex.page, 21 Oct 2026
AI privacy: Lex says it does not train AI models on customer content without explicit written permission and uses OpenAI, Anthropic and Together.ai vendors with policies against training on customer data. · lex.page, 5 Oct 2026
AI training policy: Lex says it does not train models on customer content without explicit written permission and would notify users if that policy changed. · lex.page, 21 Oct 2026
AI writing tools: Lex offers AI feedback for drafts, brainstorming and rewrites, plus commands and one-click title ideas. · lex.page, 5 Oct 2026
API: Lex publishes a public API documentation site at docs.lex.page. · docs.lex.page, 21 Oct 2026
API documentation depth: The public documentation currently exposes an introduction and documentation index, with no detailed endpoint or SDK material visible on the opened page. · docs.lex.page, 21 Oct 2026
Ask Lex chat: Ask Lex provides conversational help about a document or highlighted passage. · lex.page, 21 Oct 2026
Backups: Lex says Heroku Postgres continuous protection allows database rollback to any point during the previous four days. · lex.page, 21 Oct 2026
Brand voice controls: Yes · lex.page, 23 Sept 2026
Browser extension: No · lex.page, 23 Sept 2026
Checks: Checks provides line-level suggestions for brevity, grammar, readability and related edits. · lex.page, 21 Oct 2026
Collaboration: Documents and folders can be shared, and collaborators can edit together in real time through links. · lex.page, 21 Oct 2026
Company facts: LinkedIn lists Lex as privately held, founded in 2023, headquartered in San Francisco, with 2–10 employees. · linkedin.com, 21 Oct 2026
Company legal name: Lex’s Terms identify the provider as Lex, Inc. · lex.page, 21 Oct 2026
Customization: Lex supports custom reusable prompts and shared context tags that give its AI background about a team's voice, goals and past work. · lex.page, 5 Oct 2026
Custom prompts: Users can create reusable prompts and share them with collaborators. · lex.page, 21 Oct 2026
Desktop app: No · lex.page, 23 Sept 2026
Founder: Citybiz identified Nathan Baschez as Lex’s 2023 founder and said Lex spun out of Every Media. · citybiz.co, 21 Oct 2026
Free account limits: Free users are limited to 30 Ask Lex messages per day, five saved prompt runs per month and a low daily AI processing budget. · lex.page, 5 Oct 2026
Free plan: Yes · lex.page, 23 Sept 2026
Funding: Citybiz reported on August 24, 2023 that Lex raised $2.75 million in seed funding led by True Ventures. · citybiz.co, 21 Oct 2026
Integration: The Kit integration analyzes recent and high-performing newsletters to create custom prompts for drafting in the user's voice and suggesting subject lines, and can send finished writing to Kit. · lex.page, 5 Oct 2026
Integrations: The documented native integration is with Kit, formerly ConvertKit, for analyzing newsletters and sending drafts back to Kit. · lex.page, 21 Oct 2026
Intended users: Lex says it is for writing that needs editing and revision, including academic papers, customer-facing copy, important emails and fiction. · lex.page, 5 Oct 2026

Lex