How to Get System-Wide Grammar Checking on Mac
Most grammar checkers only work in browsers or specific apps. If you want grammar correction in every app on your Mac — Mail, Slack, VS Code, Notes, Discord, and everything else — here are your options in 2026.
The Problem with Most Grammar Checkers
Grammarly, the most popular grammar checker, works best in browsers. It has a Mac desktop app, but it only integrates with specific applications. If you switch to VS Code to edit a commit message, Notes to jot down a thought, or Terminal to write a script comment — Grammarly can't help.
The same is true for most grammar checkers. LanguageTool has a Mac app, but it doesn't work in all applications. ProWritingAid is limited to its own editor and specific integrations. QuillBot is browser-only.
What Mac users actually need is a grammar checker that works system-wide — in every text field, in every app, without exception.
What macOS Offers Built-In
macOS has two built-in options for grammar checking:
1. Spell Check (macOS 10.6+)
The classic red-underline spell checker works system-wide in most apps via the macOS text system. But it only catches spelling errors — not grammar, style, or punctuation issues. And it's limited to basic dictionary matching.
2. Apple Writing Tools (macOS 15+)
Apple Intelligence added Writing Tools in macOS Sequoia. It can proofread, rewrite, and summarize text. But it only works in Apple apps (Mail, Notes, Pages, Safari) and select third-party apps that explicitly support it. It also requires Apple Silicon with 8GB+ RAM, and grammar detection is basic.
Neither option provides true system-wide grammar checking with AI-level accuracy.
System-Wide Grammar Checkers for Mac
Here are the tools that come closest to true system-wide grammar checking on Mac:
1. FlowWrite — True System-Wide via Keyboard Monitoring
FlowWrite takes a unique approach: it runs as a menu bar app and uses macOS Accessibility APIs to intercept text selection across every application. Select any text, press Tab, and AI corrects it in place.
This works in Mail, Slack, VS Code, Chrome, Safari, Discord, Notes, Terminal, Pages, Word, Notion, Bear, Obsidian — literally any app that supports text selection. No per-app integrations needed.
- Works in every Mac app
- 5 modes: correct, translate, shorten, expand, style
- All languages supported
- Free (20/day) or $2.99/month
- Privacy-first — text never stored
2. Grammarly Desktop — Partial System-Wide
Grammarly's Mac app provides inline suggestions in some applications, but coverage isn't universal. It works well in browsers and has integrations with specific apps, but many native Mac apps aren't supported.
- Good in browsers and Google Docs
- Limited in native Mac apps
- $12/month (annual) for full features
- Requires account
3. LanguageTool Desktop — Some Apps
LanguageTool has a Mac desktop app that provides a floating suggestion window. It works in more apps than browser-only tools, but doesn't cover everything.
- 30+ languages
- Open source core
- $5/month for premium
- Doesn't work in all apps
4. macOS Spell Check + Apple Writing Tools
The free option: use macOS's built-in spell check for basic typos, and Apple Writing Tools for proofreading in Apple apps. Free, but very limited in scope and accuracy.
Comparison
| Tool | Coverage | Approach | Price |
|---|---|---|---|
| FlowWrite | Every app | Keyboard monitoring + selection | Free / $2.99/mo |
| Grammarly | Browsers + some apps | Per-app integration | Free / $12/mo |
| LanguageTool | Some apps | Floating window | Free / $5/mo |
| Apple Writing Tools | Apple apps only | Context menu | Free |
| macOS Spell Check | Most apps | Text system hook | Free |
Our Recommendation
If system-wide coverage is your priority, FlowWrite is the only tool that works in every Mac application without exception. Its keyboard-driven approach (select + Tab) means zero friction — no copy-paste, no switching windows, no waiting for inline suggestions to appear.
Start with the free tier (10 corrections/day, all features, no account needed) and see if the workflow fits how you write.