Emacs’s built-in ispell package handles spell-checking and correction, while flyspell provides on-the-fly checking and highlighting of misspellings.

Emacs has a spell checking feature (flyspell-mode), that check spelling errors while you type, much like all other modern editors, word processors, email programs, or text box in browsers. However, emacs's spell checking feature is much worse than the spell checker in browsers or any commercial editor.