Compare software

MailCatcherPapercut SMTP
Free

Free and open source under the MIT License.

 Free

Free and open source under the Apache-2.0 licence.

macOS, Linux, Web, Command line Windows, Self-hosted
  • Captures email locally for development
  • Shows HTML, plain text, and source views
  • Catches test emails without sending them
  • Simple desktop interface for reading captured messages
  • Requires Ruby 3.3 or newer
  • Email encoding support is incomplete
  • Meant for testing, not a real mail server
  • Desktop app is Windows-only
Downloadable app, Web application Downloadable app, Self-hosted
Open source Open source
License: MIT License: Apache-2.0
Not stated if an account is needed No account needed
Not stated if it works offline Works offline

Checked October 8, 2026

Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.