Suggest an alternative to

email-2FA-spring-boot

Email based 2FA implementation using Spring-boot and Java-mail API

Why do you think that https://github.com/jhalterman/expiringmap is a good alternative to email-2FA-spring-boot

A URL to the alternative repo (e.g. GitHub, GitLab)

Here you can share your experience with the project you are suggesting or its comparison with email-2FA-spring-boot. Optional.

A valid email to send you a verification link when necessary or log in.