Is Grammarly Safe to Use on Mac? A Privacy Analysis

Grammarly is safe for most personal use - it is not malware and millions of people use it without issue. The meaningful concern is that every word you type in a covered field is transmitted to Grammarly's servers. For sensitive or confidential writing, that distinction matters. If you want a privacy-first alternative, Charm corrects everything on-device, with no cloud connection at all.

What does Grammarly actually do with your text?

When you type inside a Grammarly-covered field - a browser text box, a document in the Grammarly desktop editor, or a field covered by its keyboard on mobile - your text is sent to Grammarly's servers for processing. The correction happens in the cloud, not on your device. This is how Grammarly delivers real-time suggestions: it analyses your writing remotely and returns results.

Grammarly's privacy policy states that they collect the text you submit for checking, along with usage data and account information. They use this data to operate and improve their product, and they state clearly that they do not sell personal data to third parties. However, "not selling" is different from "not using." Aggregated and anonymised text data is used for product improvement, which means your writing - however private you consider it - contributes to Grammarly's training pipeline once it leaves your device.

According to Grammarly's own transparency reporting, the company processes text for over 30 million daily active users. That is an enormous volume of sensitive personal and professional writing passing through a single commercial server infrastructure every day.

Is Grammarly actually dangerous?

No, not in the way a virus or spyware is dangerous. Grammarly is a legitimate, well-funded company with a published privacy policy and terms of service. For the vast majority of users writing blog posts, social media captions, personal emails, or school assignments, the privacy risk of using Grammarly is comparable to using Google Docs - low for personal content, but worth understanding before you type anything sensitive.

The concern is not that Grammarly is malicious. The concern is that any cloud-dependent service creates data exposure risk that a fully local tool does not. When data leaves your device, it enters a server infrastructure that can, in principle, be breached, subpoenaed, acquired, or repurposed. The risk is real even if the probability is low for any single user.

What happened with Grammarly's 2018 security incident?

In February 2018, security researcher Tavis Ormandy from Google's Project Zero disclosed a vulnerability in Grammarly's Chrome extension. The bug exposed user authentication tokens in a way that allowed any website to access a user's Grammarly account, including their stored documents and correction history. Grammarly patched the vulnerability within hours of the disclosure - a response time that security researchers praised.

No confirmed large-scale data theft was attributed to the vulnerability before it was patched. But the incident illustrated a fundamental point: when your text lives on an external server, a single software bug anywhere in that infrastructure can expose it. Grammarly handled the disclosure responsibly, but the exposure was real. A tool that never sends your text to a server cannot have this category of vulnerability.

Why do some organisations ban Grammarly entirely?

Law firms, healthcare providers, and financial institutions have policies that prohibit sending client or patient data to third-party services - regardless of that service's privacy policy. This is not about distrust of Grammarly specifically; it is about regulatory requirements and professional obligations.

Attorney-client privilege requires that confidential legal communications remain private. HIPAA requires that protected health information not be disclosed to unauthorized parties. Financial regulators impose similar data handling restrictions. Grammarly's privacy policy, however well-intentioned, does not satisfy these legal obligations because the data leaves the organisation's control the moment it is transmitted to an external server.

A 2022 survey by the ABA's Legal Technology Resource Center found that data privacy concerns were cited by 43% of law firms as a reason for restricting or banning writing assistant tools. Many of those firms specifically cited cloud-based processing as the disqualifying factor.

When is Grammarly's privacy risk genuinely low?

For casual personal writing, the privacy risk of using Grammarly is acceptable for most people. If you are drafting a tweet, editing a blog post about your weekend, writing a product review, or composing a casual email to a friend - there is no sensitive information at stake. Grammarly processes this kind of content exactly as advertised, and the privacy implications are similar to any other cloud productivity tool you already use.

The risk scales with the sensitivity of what you are writing. Personal content with no confidential information: low risk. Work emails discussing client strategy: moderate risk. Legal documents, medical notes, financial records, or anything protected by professional privilege: meaningful risk that many organisations consider unacceptable.

What is the on-device alternative for Mac?

Charm is a native macOS menu bar app that corrects spelling, fixes grammar, and predicts words entirely on your Mac. No text ever leaves your device. There is no account to create, no server connection, and no data collection of any kind. The app uses Apple's on-device frameworks to process your keystrokes locally, in under 200 milliseconds, across every Mac app - Mail, Slack, Notes, VS Code, Pages, and everything else.

Unlike Grammarly's browser-only Mac coverage, Charm works system-wide. You get three features: Spells for real-time spelling correction, Polish for sentence-level grammar fixing, and Oracle for contextual next-word prediction with tab-to-accept. It requires macOS 14 Sonoma or later and costs $9.99 as a one-time purchase with no subscription.

For a broader look at how Charm and Grammarly compare on features, coverage, and price, see the full Charm vs Grammarly comparison. If you are exploring other options, the best Grammarly alternatives for Mac guide covers the full landscape.

Frequently asked questions

Is Grammarly safe to use on Mac?

Grammarly is safe for casual personal writing. It is not malware. However, every word you type in covered fields is transmitted to Grammarly's servers for analysis. For anyone handling confidential documents, legal material, medical records, or sensitive business communications, this is a genuine data handling concern worth understanding before installing.

Does Grammarly store everything I type?

Grammarly processes your text on their servers and uses aggregated, anonymised data to improve their product. They state they do not sell personal data to third parties. However, your text does leave your device and is processed remotely - that is the core privacy consideration for anyone handling sensitive material.

Was Grammarly involved in a data breach?

In 2018, Grammarly's Chrome extension had a vulnerability that exposed user authentication tokens to any website that requested them, potentially allowing access to stored documents. Grammarly patched it within hours. No large-scale theft was confirmed, but the incident showed that cloud-dependent tools carry exposure risks that fully on-device tools do not.

Why do law firms and healthcare providers ban Grammarly?

Many legal, healthcare, and financial organisations prohibit sending client or patient data to third-party servers. Grammarly's cloud-based processing is incompatible with attorney-client privilege, HIPAA requirements, and financial data regulations. On-device tools like Charm avoid this issue entirely, since no text ever leaves the device.

Is there a grammar tool for Mac that does not send data to the cloud?

Yes. Charm is a native macOS app that corrects spelling, fixes grammar, and predicts words entirely on-device. Your keystrokes never leave your Mac. There is no account, no server, and no data collection. It works in every Mac app for a one-time payment of $9.99.