Can we rebuild it?

Can we rebuild Grammarly: AI Writing Assistant and Grammar Checker App?

Build a Chrome extension like Grammarly: AI Writing Assistant and Grammar Checker App — a Grammarly: AI Writing Assistant and Grammar Checker App alternative you own.

If you want to build your own Grammarly: AI Writing Assistant and Grammar Checker App alternative, you can ship a private Chrome extension in one session. Using standard browser APIs and your own LLM key, you can replicate context-aware grammar correction, tone adjustment, and text drafting across any input field on the web.

The listing record

What Grammarly: AI Writing Assistant and Grammar Checker App does

Grammarly for Chrome is your always-on AI partner for clearer, more compelling communication. From brainstorming ideas to final edits, Grammarly’s advanced AI helps you write faster and with more confidence. It works across everything you write, whether it’s an email, a school paper, or a business proposal. Advanced AI support you can count on: • Generate one-click drafts to help you start faster • Build outlines to organize ideas clearly • Rewrite sentences for flow, clarity, and engagement • Adjust tone and word choice for any audience • Check originality with built-in plagiarism detection and AI content safeguards And now, with Superhuman Go, you can go beyond writing. Go works alongside you in Chrome to streamline tasks and minimize interruptions—combining Grammarly’s trusted AI writing support with tools that help you stay focused and productive.

What the store says

★ 4.5 from 43K ratings · 39M users

Pulled live from the Chrome Web Store listing at analysis time.

Can PlugThis rebuild Grammarly: AI Writing Assistant and Grammar Checker App?

What you'd plug into

Why build your own Grammarly: AI Writing Assistant and Grammar Checker App alternative

• Complete privacy with zero data mining of your keystrokes
• Bring your own LLM (Claude 3.5 Sonnet, GPT-4o, or local models)
• Custom tone presets and specialized system prompts
• No forced upsells or feature lockouts

What it costs vs what you'd save

The starter prompt

Build a writing assistant Chrome extension that injects a subtle floating action button next to selected text in any input or contenteditable area. When clicked, provide options to fix grammar, change tone, shorten, or expand the selection using an LLM API key configured in the options page. Replace the selected text directly in the active field when the user accepts the suggestion.

Features you could add that Grammarly: AI Writing Assistant and Grammar Checker App doesn't have

Because you own the code, these are a follow-up prompt away — tap one to add it to the prompt above.

• Custom Style Guides — Inject company-specific acronyms, banned words, and style rules into every rewrite prompt.
  + add to prompt
• Local LLM Mode — Connect directly to Ollama for offline, zero-leak text rewriting.
  + add to prompt

Questions about rebuilding Grammarly: AI Writing Assistant and Grammar Checker App

How to build it yourself

1. 1
   Open PlugThis and start a new build

   Head to PlugThis and start a new Chrome extension. You're describing a Grammarly: AI Writing Assistant and Grammar Checker App alternative you'll own outright — no store subscription.

2. 2
   Paste the starter prompt

   Paste the starter prompt above. PlugThis expands it into a full Manifest V3 extension — popup, content scripts, and service worker included.

3. 3
   Connect your own keys

   Wire in Anthropic / OpenAI API using your own account — the build uses your credentials, so there's no per-seat fee.

4. 4
   Review, tweak, and load it

   Review the generated code, ask for tweaks in plain English, then download and load the unpacked extension in Chrome to try it.

5. 5
   Publish it (optional)

   When you're happy, publish your Grammarly: AI Writing Assistant and Grammar Checker App alternative to the Chrome Web Store — or just keep it as a private tool for yourself.

More teardowns

We run the same teardown on any Chrome extension — what it does, whether a self-built alternative holds up, and the prompt to make one. Tear down another extension, or see the extensions we've actually rebuilt and filmed — real build times, real prompts, real recordings.