Debug Mail is described as 'Easy to use mail server' and is an website in the Development category. There are more than 10 alternatives to Debug Mail, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and SaaS. The best alternative is MailHog, which is both free and Open Source. Other great sites and apps similar to Debug Mail are Mailtrap (Freemium), FakeSMTP (Free, Open Source), testmail.app (Freemium) and MailDev (Free, Open Source).
QA tool for automating end-to-end email tests. Get unlimited private email addresses and inboxes for testing new user signups, transactional emails and drip campaigns, deliverability and spam scores, etc. Integrates with your CI/CD workflow. Includes spam testing.
MailCatcher runs a super simple SMTP server which catches any message sent to it to display in a web interface. Run mailcatcher, set your favourite app to deliver to smtp://127.0.0.1:1025 instead of your default SMTP server, then check out http://127.0.0.