AppMazing is thrilled to have just launched Typolyin the app store.
Typoly checks against tens of millions of typo combos in domains (gamil, yhoo, comcst) and extensions (.ocm vs .com etc)
When a typo is suspected at checkout, your customer is prompted and given the option to change/correct or keep it as is. (prompt can be embedded or modal window)
When a correction is made, the order is tagged in your order admin with 'typoly' making them very easy to find allowing you to resend their order confirmation (but even if you don't, they will receive subsequent updates such as tracking which addresses the issue prior to your customers reaching out in frustration.