Litmus is an email marketing platform for creating and optimizing emails.

Mail Tester is an email testing tool for newsletter spam score and quality, used by marketers and businesses.

Validity provides data quality, email verification (BriteVerify), and deliverability (Everest) solutions to help marketers achieve end-to-end marketing success.

Email on Acid is an email testing and analytics platform for email marketers and developers.

MailGenius is an email testing tool that helps optimize email deliverability and avoid the spam folder with human-friendly solutions and live chat.

Mail.tm is a free, secure, and anonymous temporary disposable email service designed to protect personal inboxes from spam, bots, and phishing.

Mailsac is a disposable email testing platform designed to empower QA and Software teams with integrations for testing application email delivery.

Mailinator is an email and SMS workflow testing tool for developers and QA teams.

Gophish is the best open-source phishing framework for testing your organization's exposure to phishing and is used by security professionals.

Ethereal Email is a fake SMTP service for testing email functionality.

MailSlurp is a messaging platform for developers, QA teams, and marketing, providing email and SMS APIs for testing and automation.