MailCatcher is described as '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' and is an app in the office & productivity category. There are more than 25 alternatives to MailCatcher for a variety of platforms, including Web-based, Mac, SaaS, Linux and Windows apps. The best MailCatcher alternative is MailDrop, which is both free and Open Source. Other great apps like MailCatcher are MailGrab, Mailpit, MailHog and Mailcatch.app.
Mailsnag lets you build resilient SMTP integrations while protecting you from spamming customers during testing on QA and Staging environments. It is like Chaos Monkey for SMTP integrations.
United States
DevMail is an email sandbox service for software developers. It allows developers to capture emails from various environments and inspect HTML, text, source code, raw headers, and attachments, and improve deliverability by analyzing email spam scores.
United Kingdom
Disposable email inboxes via API for testing signup and authentication flows, with automatic extraction of one-time passwords and magic links.
