Grammarly AI vs Lex

Grammarly AI and Lex are both grammar & style checkers tracked by AIDiveForge. Below is a side-by-side comparison of pricing, capabilities, platforms, and ownership — sourced from each tool's live website and verified before publishing.

Grammarly AI

Grammarly sits in your browser and writing apps, flagging mistakes as you type—grammar, spelling, tone, clarity. It's useful if you write emails, documents, or social posts and want a second pair of eyes without leaving your workflow. The free tier covers basics; Premium ($12/month) adds tone detection and advanced rewrites. The catch: the free version is genuinely limited, and Premium's AI-powered suggestions sometimes miss context or feel prescriptive. It works best for high-stakes writing where accuracy matters more than speed.

Lex

Lex is a browser-based collaborative writing editor from Lex, Inc., aimed at writers who want AI feedback woven into the drafting process rather than pasted in from a separate window. The AI Feedback feature lets you ask for critique, rewrites, or brainstorming directly against your draft, while commands surface options like word suggestions and idea lists without leaving the keyboard. Versions let you test a rewrite without nuking what you already have — a small feature that matters more than it sounds the third time you regret an edit. Live collaboration and mobile web access work link-first, no app required. Track Changes is listed as coming soon, which is a gap that teams used to Google Docs comment workflows will feel immediately.

Attribute	Grammarly AI	Lex
Pricing	Paid	Paid
Price	$12/mo	—
Free trial	No	No
Open source	No	No
Has API	Yes	No
Self-hosted option	No	No
Platforms	Web, iOS, API	Web, iOS
Languages	95+ languages	—
Released	2009	—
Pros	Real-time feedback Grammar and spelling corrections Integrated with popular platforms	AI feedback runs against your actual draft in context, so you get critique and rewrites without copying text into a separate chat window and losing the thread of the edit. Versions let you test a rewrite without overwriting your original, which means you stop treating undo history as a safety net and start making bolder edits. Link-based collaboration requires no app install from collaborators, so sharing a draft for real-time review does not become an onboarding task. Mobile web access means the document is reachable from any device without a native app, so you are not locked to a desktop to review feedback on the go. Keyboard-driven commands for word suggestions and idea generation keep your hands off the mouse during drafting flow, which matters when momentum is the thing you are protecting.
Cons	Limited free tier accounts Subscription required for advanced features	Track Changes is not yet available — listed as coming soon on the vendor page. Teams that rely on marked-up revision trails (academic editors, legal reviewers, anyone who needs a documented record of what changed and who changed it) cannot use Lex as their primary review tool and will route documents back to Google Docs or Word for that stage. There is no API and no self-hosted option. Any team building a writing-adjacent product, automating document processing, or operating under data-residency requirements hits a hard wall here — at which point they move to an editor they can control or integrate, not a closed SaaS surface. The AI feedback and commands are chat- and shortcut-driven rather than structured. For writers who need rubric-based feedback (grade this against APA style, check for passive voice across the document) rather than conversational suggestions, the tool does not provide that systematically — and those writers end up maintaining a separate grammar or style checker alongside Lex.

Bottom line

Only Grammarly AI exposes a public API. Choose based on which difference matters most for your workflow.

Frequently asked questions

What is the difference between Grammarly AI and Lex?

Grammarly AI is Paid, while Lex is Paid. Compare pricing, free trial, API, platforms, and pros/cons in the table above on AIDiveForge.

Is Grammarly AI better than Lex?

It depends on your workflow. Use the side-by-side attributes (pricing, open source, API, self-hosted, platforms) to decide. AIDiveForge does not rank a universal winner — we publish verified facts so you can choose.