A simple email typo check at signup can silently recover lost users

A common but invisible problem in signup flows occurs when users mistype their email domain — such as 'gmail.co' instead of 'gmail.com' — and never receive a confirmation message. Unlike hard bounces, these errors produce no logs or complaints, leaving only an unexplained gap between form submissions and verified accounts. A lightweight fix uses edit-distance comparison to match the typed domain against known-good domains, then prompts the user with a 'Did you mean?' suggestion rather than rejecting the input outright. An API approach can flag such entries with a 'typo_suspect' reason and return a corrected suggestion when MX record checks fail on the submitted domain. Developers are cautioned against auto-correcting silently, as overly aggressive substitution could route mail to unintended recipients — the suggested approach is always to prompt users to confirm any correction themselves.