In short: there are many Yahoo email address formats that are legitimate, but were created in the past. However, all new Yahoo emails end with @yahoo.com.
Back then, Yahoo used national TLDs for email addresses (yahoo.co.uk, yahoo.co.in, etc.) depending on the language and location the email address was created from. Luckily, Yahoo discontinued this practice.
Don't forget to check out our Yahoo Username Availability Checker
In fact, you could even create a Yahoo email ending with @rocketmail.com (on rocketmail.com domain). This is no longer possible, but of course, the email addresses ending with rocketmail might still be valid!
Make sure to always use the correct TLD when sending an email to yahoo email address. TLDs are not interchangeable.
When it comes to the format of newly created Yahoo emails, all of them end with @yahoo.com. Say goodbye to national TLDs that so often caused email not being sent to the correct address.
Here are some examples of valid Yahoo email formats, emails ending like this can still be active, even if they no longer register new emails under these domains:
Be careful about disposable email addresses provided by Yahoo!
Yahoo allows you to create a temporary disposable email account in a similar format as your main email. Actually, they allow you to have up to 500 disposable aliases at a time.
Check out this guide on how to check if any email address is valid.
Here's how Yahoo disposable email address is formatted:
Base name is your current base part of the email and the keyword is any word you want.
Are Yahoo email TLDs interchangeable?
No, emails with the same base name on different TLDs are completely separate. Be careful when sending an email to use the correct TLD.