100% private
No intermediate server, no account, no data collection. Your text only goes to the AI provider of your own key.
Comparison
Best AI spell checker: the 2026 comparison
Antidote, Grammarly, MerciApp or Correctify: which one should you pick to fix text with AI? We compare price, privacy, languages and features to help you decide.
Free · No account · Windows, Chrome, Firefox & Thunderbird
The best AI spell checker depends on your priorities: price, languages, privacy, integrations. Here’s a clear comparison of the four best-known options (Correctify, Antidote, Grammarly and MerciApp) so you can choose with confidence.
The comparison at a glance
| Criterion | Correctify | Antidote | Grammarly | MerciApp |
|---|---|---|---|---|
| Price | Free (your key) | Paid | Freemium + Premium | Freemium |
| No account | Yes | No | No | No |
| No intermediate server | Yes | — | No (cloud) | No (cloud) |
| Fixes French | Yes | Yes | Limited | Yes |
| Auto multilingual | Yes | FR / EN | Mostly EN | Mostly FR |
| Outside the browser | Any Windows app | Connectors | Office / apps | Depends on plan |
| Choice of AI | Yes | No | No | No |
| Rewriting / tone | Yes | Yes | Yes | Yes |
| Offline | No | Yes | No | No |
Comparison provided for guidance (May 2026). Other vendors’ plans may change: check the details on their official websites.
Why choose Correctify
Truly free
No subscription, no ads. You use your own API key: Google Gemini’s free tier is plenty for daily use.
Right-click, everywhere
Browser, email and any Windows program. No connector to install app by app.
Multilingual, auto-detected
The language of your text is detected automatically and fixed in place. Never translated.
Gemini, ChatGPT or Claude
You pick the AI through your API key and stay in control of the service and the cost.
Correction and rewriting
Spelling, grammar and style. On Windows, you also get tone presets: professional, concise, polite…
Our verdict
There’s no single winner: Antidote shines with its dictionaries and offline mode, Grammarly with its English writing assistant, MerciApp with its French integration. But if your priority is to fix text for free, with no account, in every app and every language while keeping your text private, Correctify stands out. Give it a try, it’s free.
Frequently asked questions
What is the best AI spell checker?
It depends on your priorities. For rich dictionaries and offline use: Antidote. For English: Grammarly. For French as SaaS: MerciApp. To fix text for free, with no account and everywhere: Correctify is the most versatile.
Is there a completely free AI spell checker?
Yes: Correctify is free because you use your own API key. Google Gemini’s free tier is enough for daily use, with no subscription.
Which checker is best for privacy?
Correctify has no intermediate server: your text goes straight to the AI provider of your key. Cloud tools (Grammarly, MerciApp) process text on their own servers.
Which checker fixes both French and English?
Correctify detects the language and fixes French as well as English (and many more). Antidote handles French and English; Grammarly is mostly English; MerciApp focuses on French.