An AI spell checker no longer just underlines mistakes in red: it rewrites your sentence correctly, taking meaning and context into account. And contrary to popular belief, it can be completely free. Here’s how it works, and how to use it everywhere you write.

What is an AI spell checker?

Classic checkers compare your words against a dictionary and fixed grammar rules. An AI spell checker relies on a large language model (Google Gemini, ChatGPT or Claude) that truly understands the sentence. The result: it fixes spelling, grammar, conjugation and clumsy phrasing, in nearly every language, without ever translating your text.

Why can an AI checker be free?

Most online AI checkers charge a subscription. Correctify flips the problem around: you use your own API key with the AI provider of your choice. Creating a key is free, and Google Gemini’s free tier is more than enough for everyday text correction. The tool itself stays 100% free and ad-free.

Another major benefit: your text goes through no intermediate server. It travels straight from your device to the AI provider, then the correction comes back. Nothing is stored.

Classic checker or AI checker: which to pick?

  • Spelling and grammar: both can do it, but AI handles tricky agreements and broken sentences better.
  • Style and clarity: only the AI checker rephrases a confusing sentence to make it readable.
  • Context: AI tells apart words that sound alike based on the sentence’s meaning.
  • Languages: AI detects the language automatically and fixes it in that language, with no setting.

How to fix text in one click

With Correctify there’s no copy-pasting into an external site. You fix text right where you write it:

  • In your browser with the Chrome or Firefox extension: select text, right-click, “Fix the text”.
  • In your emails with Thunderbird.
  • In any software with the Windows app: a single keyboard shortcut fixes the selected text in place.

In short

A free AI spell checker is possible as long as you keep control of your own API key. You get a sharper correction than a classic checker, in every language, right where you write. Give it a try, it’s free.