MailMug.net is described as 'Capture SMTP traffic from staging and dev environments. Easily validate email content text or HTML/CSS. Utilize an Email Sandbox to thoroughly examine and troubleshoot emails within staging, development, and quality assurance (QA) environments prior to sending them to recipients' and is an website in the security & privacy category. There are more than 25 alternatives to MailMug.net, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and SaaS apps. The best MailMug.net alternative is Mailpit, which is both free and Open Source. Other great sites and apps similar to MailMug.net are MailGrab, MailHog, Mailcatch.app and Mailtrap.
MailDotNull is a local mail catcher for development. It emulates the HTTP send APIs of popular email providers (Resend, SendGrid, Mailjet, Mailgun, Postmark, Brevo, Amazon SES) plus plain SMTP with STARTTLS and SMTPS.
Create email addresses on demand. Send and receive real emails and attachments from code. Rest API and developer kits available.
Email Testing for QA & Development Teams. Catch every email your product sends, analyze it's contents, follow links and test deliverability all via the Mailosaur API.
United Kingdom
Ethereal is a fake SMTP service, mostly aimed at Nodemailer users (but not limited to). It's a completely free anti-transactional email service where messages never get delivered.
Origami SMTP was created with the idea to have a fake email server for testing purposes that supported TLS. This is because the code the developer was working on at the time had several hard coded values enforcing TLS so most other solutions would not work.
Sendria (formerly MailTrap) is a SMTP server designed to run in your dev/test environment, that is designed to catch any email you or your application is sending, and display it in a web interface instead of sending to real world.
Poland
EU
testmail.app is an email testing platform for developers and QA teams. Create unlimited test email addresses on the fly using namespaces and tags, with no inbox setup required. Tags make it easy to isolate emails between users and parallel test runs.
LunaticSMTP is a dummy SMTP server with desktop GUI for testing email sending applications.
A local SMTP server with email display, used mostly for development of other apps. Think unlimited Mailtrap that runs on your own computer.
FranceEU
Sunnybox is a fully featured hosted service for handling your email accounts. Fetch, send and analyze your emails through a single, robust API. Easy email processing for developers.
GermanyEU
