What are some alternatives?
When comparing Ruler and MailHog, you can also consider the following products
Printix - Printix is a cloud-based print management platform.
Mailtrap.io - Mailtrap is a fake SMTP server for development teams to test, view and share emails sent from the development and staging environments without spamming real customers
LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
DummySMTP - Simplify testing the email functionality of your application with a free DummySMTP inbox.
PrinterLogic - PrinterLogic is an enterprise print management software.
Debugmail - Easy to use mail server for developers