Trumail is a free and open source email validation/verification system. It is available in three forms, the Golang client library verifier for use in your own Go projects, a public API endpoint (more info: https://trumail.io), and a public Docker image on DockerHub (see: https://hub.docker.com/r/sdwolfe32/trumail/).
NOTE: It is highly recommended (due to potential Heroku IP blacklisting resulting in failed validations) that you host the service yourself either using a Docker image or by forking and serving this project on your own instance. However, self-hosting Trumail requires bidirectional communication on port 25 which most residential ISPs restrict. AWS and Digitalocean both allow this.
Trumail alternatives and similar packages
Based on the "Email" category
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