Grammarly grammarly.com

Can AI replace Grammarly?

Q: Can AI replace Grammarly?

Half-bot. You can build grammar checks and rewrites, but Grammarly's moat is cross-app extensions, inline UX, enterprise controls, writing telemetry, and long-running language quality.

You can build grammar checks and rewrites, but Grammarly's moat is cross-app extensions, inline UX, enterprise controls, writing telemetry, and long-running language quality.

Verdict: Half-bot · AI gets you partway; the hard part stays hardBuild time: multi-day

Replacing a paid app means you set it up and keep it running: hosting, updates and backups can be on you. What you give up.

Half-bot

01What it costs

$30/moPro, monthly

$360per year at that price

Checked Aug 12, 2026 · source: grammarly.com.

Plan	Monthly	Billed yearly	What you get
Free	Free	Free	100 generative-AI prompts/month.
Pro	$30	$12/mo	2,000 AI prompts/member/month; up to 149 seats; 1 style guide; 1 brand tone; 2 groups.
Enterprise	—	—	Unlimited prompts, members, style guides, brand tones, and groups.

Hidden costs: Additional Pro seats are prorated. A 7-day trial is available only for eligible accounts.

02Could AI build it for you?

The core job: Run text through LanguageTool plus an LLM rewrite/tone checker, expose a browser extension or local editor.

What a working version needs:

grammar engine/API
LLM API
browser extension
optional desktop accessibility layer
user dictionary

An important 'kinda': grammar checking is open-source, cross-app UX is the hard product.

03What you'd give up

inline suggestions everywhere
document/email integrations
tone/brand controls
enterprise admin
polished false-positive handling

They pay because suggestions appear inside the apps where writing actually happens.

04Free and cheaper alternatives

Apple Writing Toolsfree

Proofread, rewrite, shorten, or change tone almost anywhere, assuming your Apple hardware made the guest list.

Versus paying: It is restricted to supported Apple hardware and offers fewer continuous cross-app style, brand and writing analytics controls than Grammarly.

support.apple.com →

Harperopen-source

A fast English grammar checker that stays on your device and mostly keeps its opinions to itself.

writewithharper.com →

Writing Toolsopen-source

Select text anywhere, hit a hotkey, and fix, rewrite, summarize, or obey a custom instruction without opening another tab.

Versus paying: It is a manual select-text-and-hotkey workflow rather than Grammarly's continuous inline underlines and suggestions across supported apps.

github.com →

WritingToolopen-source

A LibreOffice extension with long-document checks, style statistics, profiles, and local AI; installing Java is the cover charge.

Versus paying: It is centered on LibreOffice rather than working continuously across browsers, email and arbitrary desktop apps like Grammarly.

writingtool.org →

Compare the free alternatives to Grammarly side by side →

Sponsor slot · openFeatured alternative to Grammarly. A labeled card for one relevant tool.

Book this spot →

05The build prompt

Get the Build Kit for Grammarly

The complete build prompt, plus 11 step-by-step prompts from research to launch, a design system file, a page-by-page spec, the data model and a launch checklist.

Get the Build Kit · $9 →

One-time payment. Delivered on screen and by email.