How to Keep Your Writing Private on Mac

To keep your writing private on Mac, use tools that process text on-device rather than in the cloud. Charm corrects your spelling and grammar locally using on-device ML models - no text ever leaves your Mac. macOS built-in autocorrect also processes entirely on-device. Cloud-based tools like Grammarly transmit every word you type to remote servers, which is a significant privacy risk for anyone working with sensitive documents.

Which writing tools send your text to the cloud?

Most popular writing assistants are cloud-based by design. The correction happens on their servers, not on your Mac. That means everything you type, including passwords accidentally entered in the wrong field, confidential client documents, medical notes, and legal drafts, is transmitted over the internet for processing.

Grammarly is the most widely used example. Its privacy policy explicitly states that text is processed on Grammarly's servers. The scale of this is significant: Grammarly processes over 10 billion words per week on its servers. Every word you type with Grammarly enabled is transmitted. Grammarly has also had security incidents. In 2018, a vulnerability in its browser extension could expose user authentication tokens to any website the user visited - a reminder that cloud-connected tools carry real risk beyond just data retention policies.

LanguageTool offers both a free cloud version and a paid self-hosted option. The free version sends your text to LanguageTool's servers for analysis. Only the paid Premium plan with local server mode keeps processing on your device.

Ginger and most cloud-based AI writing assistants work the same way. The processing happens remotely by necessity - the models are too large to run locally in a browser extension, so your text must travel to a server and back.

This is not a minor footnote in a privacy policy. It is the core architecture of how these tools function.

Writing tools that keep your text on-device

Two options on Mac process text entirely locally, with no network connection required for corrections.

macOS built-in autocorrect processes entirely on-device. Apple's text correction system runs in the operating system itself, with no network connection and no data sent to Apple's servers. It is private by default. The limitation is quality - macOS autocorrect handles basic spelling but misses many grammatical errors and does not learn nuanced vocabulary.

Charm is a native macOS app that uses local ML models to correct spelling, grammar, and predict words across every application on your Mac. There is no account required, no server component, and no network connection needed for its core correction features. Charm uses macOS Accessibility APIs to read and correct text in real time, entirely on your device.

Charm's architecture is worth understanding. Unlike a browser extension that sends text to a cloud API, Charm runs its correction models locally - the same way a calculator works offline. Your text is processed, corrected, and returned to the text field without leaving your Mac at any point.

Charm does offer one optional feature that uses the OpenAI API for advanced grammar analysis. This is entirely opt-in, disabled by default, and if you enable it, it uses your own API key - not a shared Charm server. Even this optional feature keeps Charm out of the data path.

For professionals who handle sensitive material, on-device processing is not optional - it is a requirement. Charm at $9.99 one-time versus Grammarly at $144 per year makes the privacy-first choice also the more economical one.

How to set up private writing on Mac with Charm

Getting Charm running takes about two minutes and requires no account creation.

Step 1: Download and install Charm. Get Charm from theodorehq.com/charm. The app is a standard macOS installer. Open it and drag Charm to your Applications folder.

Step 2: Launch Charm. Open Charm from Applications or Launchpad. The app runs as a menu bar utility - you will see the Charm icon appear in your menu bar. There is no login screen, no account setup, and no email required.

Step 3: Grant Accessibility permission. Charm will prompt you to grant Accessibility access in System Settings. Go to System Settings, then Privacy and Security, then Accessibility, and toggle Charm on. This permission allows Charm to read and correct text across all your apps. The permission is used entirely on your Mac - Charm does not transmit anything.

Step 4: Start writing. Charm is now active in every text field on your Mac. Open Notes, Mail, Slack, VS Code, or any app and start typing. Corrections happen automatically, without red underlines or interruptions.

No network connection is required after installation. Charm works completely offline.

Practical tips for writing privately on Mac

Beyond choosing the right writing tool, a few habits help ensure your writing stays private across different contexts.

Disable cloud writing tool extensions for sensitive work. If you have Grammarly or a similar extension installed in your browser, disable it before working on confidential documents. In Chrome or Safari, open the extensions manager and toggle the extension off. Re-enable it afterwards for general writing if you choose to keep using it for non-sensitive work.

Be aware that web apps have their own privacy implications. Even with Charm installed, text you type in Google Docs is processed by Google's servers regardless. Notion, Notion AI, and similar tools work the same way. On-device writing tools like Charm protect the correction layer - but the storage layer of web apps is a separate consideration. For the most sensitive drafts, write locally in an app like Pages, Notes, or Obsidian rather than in a web-based document editor.

Check browser extensions regularly. Writing-related extensions are not the only ones that can access text. Password managers, translation tools, and clipboard utilities may also read content from text fields. Periodically review what extensions are installed and what permissions they hold.

Use encrypted local storage for sensitive drafts. macOS offers FileVault to encrypt your entire disk. For particularly sensitive documents, you can also store drafts inside an encrypted disk image using Disk Utility. Combined with on-device writing tools, this keeps your drafts secure both in transit and at rest.

Frequently asked questions

Does Grammarly send my text to its servers?

Yes. Grammarly sends all text you type in its coverage areas to its remote servers for processing. Their privacy policy confirms this. Grammarly processes over 10 billion words per week on its servers. Every word you type with Grammarly enabled is transmitted. This makes it unsuitable for confidential documents, legal drafts, medical notes, or any sensitive material.

Is macOS autocorrect private?

Yes. macOS autocorrect processes entirely on-device. It requires no network connection and transmits nothing to Apple's servers. It is private by default, though its correction quality is limited compared to a dedicated writing tool like Charm.

Is Charm private?

Yes. Charm is entirely on-device. It uses local ML models, requires no account, and needs no network connection for corrections. Even Charm's optional advanced grammar feature is opt-in and uses your own API key - Charm has no server that handles your text.

Which writing tools are safe for confidential documents on Mac?

Charm and macOS built-in autocorrect are the safest options because both process text entirely on-device. Avoid Grammarly, LanguageTool's free cloud version, Ginger, and cloud AI writing assistants for sensitive material. Also note that web apps like Google Docs and Notion process text on their own servers regardless of which writing tool you use.