uChecker · macOS 
A menu-bar proofreader that never has to leave your Mac.
Select text anywhere, press your hotkey or use the Services menu, and uChecker's panel drops down from the menu bar with the check already done, tagging exactly what it changed rather than rewriting your voice. One click copies the corrected text back. Apple Intelligence and the offline system spell-checker both run on-device, so by default your text is never sent anywhere. Connect your own OpenAI- or Anthropic-compatible endpoint only if you choose to.
// features
What it actually does.
Proofread, with a paper trail
Proofread mode tags exactly what changed (spelling, grammar, punctuation) instead of handing back a silently rewritten paragraph you have to diff yourself.
Fixes mistakes, not your style
Your em dashes, curly quotes and British spelling survive a check. uChecker corrects errors, it doesn't flatten your voice into a house style.
Always a keystroke away
Trigger a check from a global hotkey, the menu-bar icon, or the macOS Services menu, without leaving whatever app you're already typing in. uChecker reads the selection and never writes to it: the result waits in the panel until you copy it.
On-device by default
Apple Intelligence and offline spelling both run locally, so your text makes no network connection unless you deliberately turn one on. No account, no analytics, no tracking SDKs.
Free spelling on any Mac
Offline spelling uses the system spell-checker and needs no Apple Intelligence, so it works on Intel Macs and older macOS versions too, and covers far more languages than the on-device model does.
Pro, bought once
Custom modes and connecting your own model endpoint are unlocked by a single in-app purchase. There's no subscription, and Apple handles the payment, not us.
// pricing
Free to check. Pay once to customize.
uChecker's core is free: Proofread and Rephrase, powered by Apple Intelligence where it's available and by the offline system spell-checker everywhere else, with no account to create and nothing to sign up for. Pro is a single one-time in-app purchase, not a subscription, and it unlocks custom modes and the ability to connect your own OpenAI- or Anthropic-compatible endpoint with an API key you supply. Purchases are processed and billed by Apple; we never see your payment details.
// requirements
What it needs.
- → macOS 14 (Sonoma) or later to run uChecker at all.
- → Apple Intelligence needs an Apple silicon Mac on macOS 26 or later, and supports a limited set of languages. It's one of several engines, so uChecker works without it.
- → Offline spelling works on any supported Mac, Intel included, with no Apple Intelligence required.
- → A custom endpoint (Pro) needs an internet connection and your own API key; the key lives only in your Mac's Keychain.