Private Writing AssistantPrivate grammar checkers: what to look for
Updated October 28, 2026
A grammar checker extension reads everything you type on websites. Five questions tell you where that writing goes. We make Private Writing Assistant, one of the options below; what we say about the others comes from their own pages, linked under Sources.
Five questions to ask
Where is the text checked?
On your own computer, or on the company's servers? If it's checked on servers, your sentences leave your computer as you type. Look for a plain statement such as “runs on your device”.
Do you need an account?
An account links what you write to your name and email address. A checker that works without one has nothing to link it to.
What is kept, and is it used for training?
Read the privacy policy: is your text stored, for how long, and can it be used to train AI models? If so, check whether that is on by default and how to turn it off.
Does it work offline?
Turn off your Wi-Fi and type a sentence with a mistake. If it is still underlined, the checking happens on your computer.
Which languages does it check?
Several private checkers cover English only. If you write in other languages, check each one you need.
How the options answer them
| Extension | Where text is checked | Account | Offline | Languages |
|---|---|---|---|---|
| Private Writing Assistant (ours) | On your computer | No | Yes, after the model download | 101 |
| Harper | On your computer | No | Yes | English |
| Chrome spell check, Basic | On your computer | No | Yes | Your Chrome languages |
| Chrome spell check, Enhanced | Google's servers | No | No | Your Chrome languages |
| Grammarly | Grammarly's servers | Yes | No | 23 |
| ProWritingAid | ProWritingAid's servers | Yes | No | English |
| Microsoft Editor (Edge only) | Microsoft's cloud | For refinements | No | More than 20 |
Each name links to a side-by-side comparison with price, rewriting, Google Docs and what your computer needs.
Facts about the other products were checked on their own pages on October 28, 2026 and are listed under Sources. Prices are in US dollars and can change.
Sources
- Grammarly Prices and Plans
- Transform your writing in languages spanning Spanish to Italian
- What do I need to use Grammarly?
- Get started with Grammarly
- Can I use Grammarly offline?
- Product Improvement and Training Control
- Does Grammarly support Google Docs?
- Pricing | ProWritingAid
- ProWritingAid for Chrome
- ProWritingAid Integrations
- ProWritingAid's Approach to AI
- What do I need to use ProWritingAid?
- Microsoft Editor browser extension retirement
- Microsoft Editor checks grammar and more in documents, mail, and the web
- Turn Chrome spell check on and off
- Basic Spell Check
- Navigating spell check using Chrome
- Harper: Free, Open Source Grammar Checker
- The Harper Chrome Extension
- Harper source code (Google Docs support)