GitHub - mailhog/MailHog: Web and API based SMTP testing

Litmus PutsMail — Test your HTML emails before sending them.

Test in real time your html emails for campaigns newsletters and others before sending them

Email Marketing Platform | Litmus

Litmus is the all in one email marketing platform that provides the tools and solutions your team needs to create effective email campaigns that convert

Email analytics | Campaign Monitor

Measure the success of your email marketing campaigns with powerful testing tools and email analytics from campaign monitor try it today

grunt-litmus

Send email tests to litmus

gulp-litmus

Send email tests to litmus

Mailtrap - Email Testing Tool #1

Inspect and debug your email samples before delivering them to your customers

Automate email tests | loved by developers & QA teams

Test new user signups transactional emails spam scores and more get started on our free forever plan with unlimited email addresses and mailboxes

MailCatcher

Email Privacy Tester - A tool to test your email client's priacy features (loading remote content)

Newsletters spam test by mail-tester.com

Mail tester com is a free online service that allows you to test your emails for spam malformed content and mail server configuration problems

Sendtest.email - Test your HTML email, ⚡4email, or text version before sending. Privacy-focused, no sign-up required!