I use email validation via MailGun for exactly this purpose with a productized service business. If we don't have a good email, then we can't deliver the service once complete. That leads to angry customers, even if the issue was a typo when they created the account. Easier to try and catch it during signup rather than at the time of delivery when emails start bouncing and you have no way to get ahold of the person.
Mailcheck is also helpful to catch things like "[email protected]" and other common typos when the user types it in:
https://github.com/mailcheck/mailcheck
Fork modified for React: https://github.com/eligolding/react-mailcheck#readme
Re:Check If Email Exists
by justinator on Friday July 02, 2021 @02:52AM
(#27708529)
I somewhat lol'd when the demo allowed "[email protected]" just fine. Guess kickstarter isn't using mailcheck anymore. Looks like it's an open issue:
Oh, yeah, that's not good. Not sure why they didn't just repoint to the suggested https://codepen.io/ianneub/pen/BajKKBy demo.
The fewer times you bounce, the better your chances of not being marked as a spammer.
This could also be useful for an ecommerce site, where you want to be able to easily contact the buyer if there's a delay, address correction needed, etc. People typo their own email at a rate that's surprising.