Spello — Spell & Grammar Checker

Free spell & grammar checker that runs 100% on your device. Private, offline, no account. Works on any Chrome — no AI chip needed.

Spello is a free spell checker and grammar checker that works entirely on your device. As you type — in search boxes, forms, Gmail, Outlook, Notion, and most websites — Spello underlines spelling and grammar mistakes in red, right in the text. Click a suggestion to fix it instantly. No account, no subscription, no sign-up. Why Spello is different: it runs 100% on your device. Your writing is never uploaded, never sent to a server, never logged, and never sold. Independent research in 2026 found that most AI writing extensions collect user data — some even capture your keystrokes. Spello was built to be the opposite: a private spell checker that keeps your words yours. FEATURES - Real dictionary spell checking with smart, pick-the-right-word suggestions - Grammar checking: a/an, "could of" → "could have", repeated words, spacing, and more - Red underlines directly in the text — even inside Gmail and other rich editors - Personal dictionary — add names and jargon so they're never flagged - Per-site on/off toggle - Lightweight — no browser slowdown - Works on any Chrome and any computer — no special AI hardware required WHAT YOU WON'T GET - No sign-up, no account - No subscription, no surprise auto-renewals - No ads, no tracking, no data collection - No network access — Spello works completely offline Whether you're writing emails, filling forms, posting online, or writing in a language that isn't your first, Spello is a fast, private, free spelling and grammar checker for Chrome — a privacy-friendly alternative to cloud-based grammar checkers. Free spelling and grammar checking that respects your privacy. Your words stay yours.