What are the best ways to check for and prevent email typos on signup forms?

Marketer from Email Geeks suggests a basic check for a valid MX-Record (or A-Record) to catch errors like "gmail.con", though it won't catch all typos.

Email marketer from Stack Overflow advocates for fuzzy matching algorithms (like the Levenshtein distance) to suggest possible corrections. These algorithms compute the number of single-character edits required to change one word into the other and will suggest if its likely its a small typo.

Email marketer from Experian explains that using real-time data validation tools which can check the syntax of the email address, verify the domain exists, and even ping the mail server to ensure it's active can catch typos and invalid email addresses at the point of entry.

Email marketer from Quora recommends implementing client-side validation to provide immediate feedback to users about the format of their email address. Suggests integrating a 'did you mean' functionality to correct common domain typos.

Marketer from Email Geeks shares that they blacklist misspelled domains and implement spelling tips in forms to help users correct mistyped email addresses.

Email marketer from Stack Overflow recommends using Regular Expressions (Regex) to validate email format on the client-side, allowing for instant feedback to the user if the entered email doesn't match the required pattern. Note: should not be solely relied upon as they do not guarentee that the email exists, only that it matches a specific pattern.

Email marketer from Reddit suggests using JavaScript to automatically suggest corrections for common email typos (e.g., "@gnail.com" becomes "@gmail.com") as the user types, improving the user experience and reducing invalid signups.

Email marketer from Mailjet shares using double opt-in which requires users to confirm their email address by clicking a link in a confirmation email which significantly reduces the risk of typos and ensures the email address is valid and belongs to the user.

Email marketer from Medium recommends regularly testing your signup forms and email validation processes. Perform A/B testing with different validation methods and form layouts to discover what works best for your specific audience.

Email marketer from Marketing Over Coffee Forums recommends using a commercial service such as Kickbox or Neverbounce to verify the deliverability of email addresses, which can identify and prevent the use of typoed or disposable addresses. These services provide real time detection of invalid emails.

Expert from SpamResource emphasizes the importance of using validation techniques that go beyond basic syntax checks. They recommend using real-time verification services that can detect disposable email addresses (DEA) and role-based addresses (like sales@) to improve list quality and sender reputation, thus reducing the risk of sending to mistyped or invalid addresses.

Expert from Word to the Wise explains that although there are vendors that provide email validation and verification services, she thinks they're largely a waste of time. She suggests focusing on clear copy on forms, and post-submission cleaning.

Expert from Email Geeks suggests checking your own bounce-suppression file for previously bounced domains and displaying a warning to users, allowing them to correct their input.

Expert from SpamResource recommends implementing a confirmed opt-in (double opt-in) process. This method requires subscribers to verify their email address by clicking on a link sent to the provided address, significantly reducing the number of typos and ensuring that only valid and interested users are added to the mailing list.

Expert from Email Geeks shares that he writes bounced domains to a suppression file and checks future sends against it to avoid repeated sending to bad domains.

Documentation from Mailgun explains that their Email Verification API checks email addresses for typos, invalid domains, and disposable email addresses. It also provides a quality score indicating the likelihood of the email address being valid and safe to send to.

Documentation from IETF specifies the formal syntax for email addresses, allowing developers to implement checks for basic structural correctness, such as the presence of an @ symbol, valid characters, and domain format.

Documentation from Google Cloud explains that using the reCAPTCHA Enterprise email fraud prevention feature can help detect and prevent email typos and disposable email addresses on signup forms. It uses risk analysis to identify suspicious email patterns.

Documentation from Microsoft details using the System.Net.Mail.MailAddress class in .NET to validate email address format, and try and catch errors. It can throw an exception if the format is invalid, which you can then handle and prompt the user to correct. Also states to not only rely on this.