ConfiA private Grammarly alternative: AI writing help that stays on your computer
If you write about other people for a living (patients, clients, employees, cases), you have probably hesitated before pasting a message into a grammar checker or an AI rewriter. You’re right to.
Where does your text go?
Writing tools work in one of two ways:
- On your device: the text stays on your computer.
- On a server: the text is sent over the internet to be analyzed. This is how most popular grammar checkers and nearly all AI rewriting tools work, including their free tiers.
For confidential writing, that difference matters more than any feature list.
On-device options
On-device writing tools have become a real category:
- Harper is a free, open-source grammar checker that runs locally, using rules rather than AI (writewithharper.com). It checks English; it doesn’t rewrite.
- LanguageTool can be self-hosted to run offline, though the setup needs a lot of disk space (Burgeon Lab).
- Several desktop apps now run AI models locally on Mac or Windows.
Always check a tool’s privacy policy and your organization’s rules: features change often.
Confi: checking AND rewriting, in your browser, on your computer
Confi combines both, in English and French, with nothing to install:
- Checks as you type: spelling and grammar (Confi uses Harper for English), plus shorthand like “pt” → “patient”. Click an underline to fix it.
- Rewrites on request: clearer, more professional, shorter, warmer, or any instruction you give the assistant.
- Translates English ↔ French.
- Protects identifiers: record numbers, dates of birth, phone numbers, names… are detected and hidden even from the local AI.
- Learns your style if you want, from your own emails (anonymized, stored only on your computer), so suggestions sound like you instead of like an AI.
The AI is the one built into Chrome, or a model downloaded once into your browser. No account, no server, free.
What on-device AI can’t do (yet)
To be fair about the trade-offs: AI that runs on a laptop is smaller than the largest cloud models. It’s very good at fixing, shortening and polishing everyday emails; it’s less suited to long, complex documents. Chrome’s built-in AI gives the best results; on other browsers Confi downloads a lighter model.