If you want writing help inside Mac apps without sending every check to a cloud service, start with TextWarden or Refine: both describe local checking as their default. For broader language support and named integrations such as Mail, Messages, Notes, Slack, and Teams, LanguageTool is a stronger fit, but its advanced checker requires an internet connection. No option is documented as working reliably in every text field, so check your specific app before switching.
What “private” and “in the text field” mean
A Mac writing assistant can read text as you type, show inline underlines, or open a correction tool with a shortcut. Those behaviors depend on the app: a product may work in Mail and Notes but behave differently in a custom editor. Likewise, “private” can mean checks run locally by default, or that the service has a different network-dependent model. The descriptions below are claims from each product’s developer or project, not independent security audits.
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Grammarly already offers Mac and browser support in apps without copying and pasting, including Apple Mail and Microsoft Word and Outlook, and says users can disable it in a particular app. Its Mac page lists macOS 10.15 or newer. The distinction to focus on when seeking an alternative is therefore the privacy model, the exact app workflow, and language coverage—not simply whether text-field checking exists. Grammarly’s Mac compatibility details explain its stated baseline.
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| Tool | How checking appears | Privacy model described by its developer | App and language fit | Cost model described |
|---|---|---|---|---|
| TextWarden | Reads the active text field and checks it; app behavior and underlines vary. | Grammar checks run locally with bundled Harper. Optional AI features use Apple Intelligence on the Mac. | Publishes an app-by-app support table; grammar checking is English-only. Language detection can suppress English checks for selected non-English passages, but does not proofread them. | Free and open source; says it has no subscription. |
| Refine | Offers checks and writing actions inside Mac apps. | Downloaded default models run locally and need no internet. Selected hosted tasks can be routed directly to a provider chosen by the user; the API key is kept in macOS Keychain. | Its About page does not list every supported app, so confirm your editor. Lists macOS 14.0 or later. | Free trial and one-time license. |
| LanguageTool for macOS | Inline underlines in supported apps; a shortcut can invoke its writing tool in other apps. | Advanced spelling, grammar, and style checking requires an internet connection. | Names Apple Mail, Messages, Notes, Word (beta), Slack (beta), and Teams (beta). Says its checker supports more than 30 languages and dialects. | Free and Premium versions with different feature coverage. |
| Harper | Its site lists browser/editor integrations and a macOS desktop option, but does not establish the desktop release status or a detailed app matrix. | Its site describes checking as local, without cloud round-trips or telemetry. | Verify the current Mac option and your exact app before relying on it. | Site says the checker is free. |
These are not equivalent feature sets. Prices and availability can change; check the linked product pages for current terms. None of the cited material supplies a comparable independent accuracy benchmark, so the table does not rank proofreading quality.
#1 Best Overall
- WIRELESS, RECHARGEABLE CONVENIENCE — Magic Keyboard with Numeric Keypad connects wirelessly to your Mac, iPad, or iPhone via Bluetooth. And the rechargeable internal battery means no loose batteries to replace.
- WORKS WITH MAC, IPAD, OR IPHONE — It pairs quickly with your device so you can get to work right away.
- ENHANCED TYPING EXPERIENCE — Magic Keyboard delivers a remarkably comfortable and precise typing experience. Its extended layout features document navigation controls for quick scrolling and full-size arrow keys. The numeric keypad is ideal for spreadsheets and finance applications.
- GO WEEKS WITHOUT CHARGING — The incredibly long-lasting internal battery will power your keyboard for about a month or more between charges. (Battery life varies by use.) Comes with a Lightning to USB Cable that lets you pair and charge by connecting to a USB port on your Mac.
- SYSTEM REQUIREMENTS — Requires a Bluetooth-enabled Mac with macOS 10.12.4 or later, an iPad with iPadOS 13.4 or later, or an iPhone or iPod touch with iOS 10.3 or later.
TextWarden: a practical local-first choice for English
TextWarden is the clearest fit if you want a free, open-source checker that is described as processing grammar locally and your writing is in English. Its project documentation says that, after Accessibility permission is granted, it reads the active text field and checks it locally with bundled Harper. Optional AI features use Apple Intelligence on the Mac, according to the project. See TextWarden’s documentation and app support table.
The published app list covers Apple Mail, Notes, Messages, Safari, Chrome, Brave, Slack, Microsoft Word, Outlook, Teams, and several chat and web apps, with app-specific exceptions. That breadth is useful, but it is not a promise that every editor exposes its text in a way the checker can handle. The project cautions that some editors provide too little information for dependable underlines or safe corrections, and replacing an entire field can remove formatting.
Rank #2
- Magic Keyboard delivers a remarkably comfortable and precise typing experience.
- It’s also wireless and rechargeable, with an incredibly long-lasting internal battery that’ll power your keyboard for about a month or more between charges.
- It pairs automatically with your Mac, so you can get to work straightaway.
- It features a USB-C port and includes a woven USB-C Charge Cable that lets you pair and charge by connecting to a USB-C port on your Mac.
TextWarden’s language detection is not multilingual proofreading. The project says it can detect 69 selectable non-English languages and suppress English checks for those passages; it does not grammar-check those languages. Its project page also mentions a browser-extension preview that requires manual installation, so treat that as a preview rather than a polished store-installed extension.
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1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteRefine: local models with optional provider routing
Refine describes itself as an offline-first assistant for grammar and fluency checks, rewrites, translations, and explanations inside Mac apps. Its default downloaded models run on the Mac, so those checks do not need an internet connection. If you choose a hosted task, Refine says you can configure selected requests to go directly to a provider you choose, with the API key stored in macOS Keychain. Refine’s About page lists macOS 14.0 or later, a free trial, and a one-time license.
Rank #3
- Magic Keyboard is available with Touch ID, providing fast, easy and secure authentication for logins and to unlock your Mac.
- Magic Keyboard with Touch ID and Numeric Keypad delivers a remarkably comfortable and precise typing experience.
- It features an extended layout, with document navigation controls for quick scrolling and full-size arrow keys, which are great for gaming.
- The numeric keypad is also ideal for spreadsheets and finance applications.
- It’s wireless and features a rechargeable battery that will power your keyboard for about a month or more between charges.
The key qualification is app coverage: the cited About page does not enumerate every supported editor. Before choosing Refine, verify that it supports the exact app and text field where you write. Its local-default and optional hosted modes also mean that “offline-first” should not be read as “every feature is always local.”
LanguageTool: wider language coverage, internet-dependent advanced checks
LanguageTool is the more suitable option if you need its stated support for more than 30 languages and dialects or want a directly named integration. Its Mac page lists Apple Mail, Messages, Notes, Microsoft Word (beta), Slack (beta), and Teams (beta). It describes inline underlines in supported apps and a shortcut that invokes the writing tool in other Mac apps; system-level checking requires Accessibility permission.
Rank #4
- Ultra Thin Wired Keyboard: Constructed with aluminum backing, the slim keyboard's height is less than that of a penny.
- Broad Compatibility: Able to work with Apple and compatible with Windows PC operating systems
- Full Sized Extended Keyboard: Easy access to media with 20 Apple shortcut keys (cut/copy/paste, iTunes control, Volume up/down, etc.) and multimedia shortcuts for Windows PC. Also, contains a ten-key numeric keypad for easy data entry.
- Plug and Play (No Drivers Required): No need to continually change or recharge batteries of wireless keyboards
- Long Cord: 4'7" (140 cm) USB cable to connect your external keyboard to the computer
There is an important privacy and capability trade-off: LanguageTool says an internet connection is required for its advanced spelling, grammar, and style checker. Its free version covers spelling, simple punctuation, and some style mistakes, while Premium shows more errors. LanguageTool’s macOS page describes the integrations, connection requirement, and plan differences. Its stated language count and features do not establish that every check is local.
Recommended Free Tools
Harper: promising local claims, but verify the Mac workflow
Harper’s official site describes local checking with no cloud round-trips or telemetry and lists browser/editor integrations alongside a macOS desktop option. However, the cited page does not establish the desktop option’s precise current release status or which Mac apps it supports. That makes Harper worth investigating if its local model matters to you, but not a confirmed turnkey recommendation for a particular text field. Check Harper’s official site for its current Mac availability and integrations.
Best Value
- Magic Keyboard is available with Touch ID, providing fast, easy and secure authentication for logins and to unlock your Mac.
- Magic Keyboard with Touch ID and Numeric Keypad delivers a remarkably comfortable and precise typing experience.
- It features an extended layout, with document navigation controls for quick scrolling and full-size arrow keys, which are great for gaming.
- The numeric keypad is also ideal for spreadsheets and finance applications.
- It’s wireless and features a rechargeable battery that will power your keyboard for about a month or more between charges.
Check compatibility and permissions before you commit
- Identify the exact app and field. A product’s app list is more useful than a broad claim that it works across macOS. Check the specific editor, compose window, or web app you use; custom text fields may behave differently.
- Confirm the interaction you want. If you want continuous inline underlines, look for explicit support in your app. A shortcut-based writing tool is a different workflow from automatic in-field checking.
- Review Accessibility access. LanguageTool requires macOS Accessibility permission for system-level checking, and TextWarden also requires it. Grant access only if you are comfortable with the app’s stated behavior and permissions.
- Test a noncritical draft. Check that underlines appear where expected and that applying a correction preserves formatting. This matters especially in editors where a correction may replace the whole field.
- Choose the language and network model deliberately. TextWarden’s grammar checks are English-only; LanguageTool states support for more than 30 languages and dialects but requires internet for advanced checks; Refine’s default models are local, with selected hosted tasks available by configuration.
- Check current terms and compatibility. Confirm the current version, supported apps, release status, and price directly with the developer before relying on a feature or purchase.
Which one should you choose?
- Choose TextWarden if you write in English, want a free open-source option, and your app is covered by its support table.
- Consider Refine if you want local downloaded models plus the option to route selected work to a provider you choose, and you have confirmed support for your editor.
- Choose LanguageTool if its broader stated language coverage and named app integrations matter more than having advanced checks run offline.
- Investigate Harper if its local-processing claims appeal to you, but first establish whether its current Mac desktop option supports your workflow.
There is no evidence here for a universal winner on accuracy or speed. The best fit is the one whose stated privacy model, language support, and behavior in your exact Mac app match your needs.
Quick Recap
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