TempMailNinja is an online service that provides free, disposable email addresses to help users keep spam and unwanted messages out of their personal inboxes. An address is generated instantly without registration, and users can receive incoming messages, including verification emails, through a live mailbox. The service is designed for temporary use with websites, online sign-ups, and other situations where users prefer not to share their regular email address.

The platform offers features including multiple email domains, address changes, message history, favorites, QR-code access, and automatic cleanup of older emails. It is mobile-friendly and available in several languages. TempMailNinja has a free plan with limited access, as well as paid Basic and Pro plans billed monthly or yearly. Paid options include expanded or unlimited limits for features such as custom domains, history, and favorite messages, along with no ads, attachment viewing, and access to premium domains. The site also publishes articles about disposable email and online privacy.