Browser extension
Clever Checker for Firefox
Every checker on the site, in the tab you are already in. Select any text, right-click, and the whole toolbox opens beside it.
Add to Firefox
Free. Signed by Mozilla, hosted here.
- Fix grammar as you type.
- See what reads as AI.
- Check it against the web.
- Free, and no signup.
How to use it
Select any text Right-click Clever Checker
Where to use it
Everywhere you browse
Google Docs
Gmail
Outlook
Microsoft 365
Slack
Discord
Notion- Every Website
Grammar
Corrections in place
Spelling, punctuation, and the words that sound the same and are not. Every correction comes with the sentence it belongs to, and applying one puts it straight back into the field you were writing in.
AI detection
How much reads as AI
A score for the passage and a reading for every sentence in it, so you can see where the signal actually is. It is an estimate of how the text is written, not a record of where it came from, and the panel says so.
Plagiarism
Find where it appears
We search the web for the phrases worth quoting, then read the pages back and measure what genuinely overlaps. You get the sources and the share of your text they cover, with a link to each one.
Rewriting
Rewrite it, in the page
Paraphrase, humanise or summarise what you have highlighted, then drop the result back into the box you took it from. Only when you ask it to: nothing is replaced behind your back.
Get it
Check where you write
Free to add, and it works with the account you already have. Pro lifts the daily limit across the site and the extension at once.
Add to Firefox
Free. Signed by Mozilla, hosted here.
FAQ
Klare Antworten
Is the extension free?
Ja. Du kannst es bis zu 5 mal am Tag kostenlos nutzen, ohne Anmeldung. Der kostenpflichtige Test hebt das Limit auf und schaltet die Stapelprüfung frei.
Ist mein Text privat?
Ja. Wenn du angemeldet bist, wird deine Prüfung in deinem Konto gespeichert und bleibt, bis du sie löschst; ohne Konto wird dein Text innerhalb von 24 Stunden gelöscht. Wir verkaufen ihn nie und nutzen ihn nie zum Trainieren, und du kannst jede Prüfung oder dein ganzes Konto jederzeit löschen.
Brauche ich ein Konto?
Nein. Jedes Werkzeug funktioniert ohne Konto. Melde dich nur an, wenn du deine Arbeit speichern und ein Abo geräteübergreifend verwalten willst.
Which browsers does it work on?
Chrome, Edge, Brave, Opera, Yandex and Vivaldi share one build; Firefox and Safari have their own. See the full list.
Can I install it manually?
Yes. The manual install for Firefox is a download and a few steps, and it runs the same build.