What does the AI grammar checker fix?

It corrects spelling, subject-verb agreement, tense drift, punctuation and apostrophes, and run-on sentences. It does not rewrite your argument or upgrade your vocabulary. If you wrote “gutted” it stays “gutted” — it just stops being “gutted’” with a stray apostrophe. That restraint matters when you are texting a friend and do not want to sound like a press release.

How do I check grammar without leaving the app I am in?

Install the TextAI keyboard once: iOS Settings → General → Keyboard → Keyboards → Add New Keyboard → TextAI, then allow full access. After that, switch to the TextAI keyboard in any app, select or paste your text, and tap Proofread. The corrected version replaces what you wrote. It behaves the same in iMessage, Gmail, Slack, LinkedIn and Notes.

Is it better than the built-in iOS autocorrect?

They solve different problems. Autocorrect fixes one word as you type it and has no idea what your sentence is about. TextAI reads the whole passage, so it catches the mistakes autocorrect creates: the wrong “their”, the tense that drifted halfway through, the question you never punctuated. Let autocorrect work while you type and run TextAI before you send.

When should you not use it?

If you are writing dialect, deliberate fragments, or a voice that breaks rules on purpose, a grammar pass will sand that off. Use the tone changer or the paraphrasing tool instead — those preserve intent rather than enforcing standard usage.