Grammar Checker

In short This runs a rule-based check entirely in your browser: repeated words, subject-verb agreement patterns, the common confusions like their and there or its and it's, spacing and punctuation, capitalisation, passive constructions, filler phrases, and sentences long enough to be worth rereading. It catches the frequent mistakes reliably and it explains the rule behind each one, which is the part that stops you making the same mistake next time. What it cannot do is understand context the way a person does. A rule-based checker cannot tell that a sentence is grammatically perfect and factually wrong, or that a passive construction is the right choice here, or that the word you meant is a real word used incorrectly — "the affect was immediate" parses fine. The tradeoff is deliberate and worth knowing: because it runs locally, your text is never sent anywhere, which matters for a contract draft, a medical letter or anything under an NDA. No cloud model, and no privacy question either.