Email Checker (email-checker.net) is a tool that does some e-mail validation. Step 1 Koha already does, but I am curious if Koha could do steps 2 and 3? How do we verify an email ? First it checks for email address format. Then make sure that domain name is valid. We also check whether itβs a disposable email address or not. In the final step, It extracts the MX records from the domain records and connects to the email server (over SMTP and also simulates sending a message) to make sure the mailbox really exists for that user/address. Some mail servers do not cooperate in the process, in such cases, the result of this email verification tool may not be as accurate as expected. The tool itself limits you to 5 checks per hour. There is a premium plan, and also an API. Only 5 lookups per hour, in free plan. Upgrade to our premium plan or use the API. This would be a great tool when creating a patron record. With the way it is worded, I don't know if the API is free to use, but if not, I'm wondering if we could incorporate the same methods in Koha?
Checking that the domain name is valid and extracting the MX records is easy enough. Connecting to the target mail server to try to check if the mailbox exists is more problematic. Depending on the usage you envision, this could be a good use case for a Koha plugin.