Best Open Source Email Software 2025

Email Software

Email MS-DOS ChromeOS Clear Filters

Browse free open source Email software and projects for MS-DOS and ChromeOS below. Use the toggles on the left to filter open source Email software by OS, license, language, programming language, and project status.

Simple, Secure Domain Registration
Get your domain at wholesale price. Cloudflare offers simple, secure registration with no markups, plus free DNS, CDN, and SSL integration.

Register or renew your domain and pay only what we pay. No markups, hidden fees, or surprise add-ons. Choose from over 400 TLDs (.com, .ai, .dev). Every domain is integrated with Cloudflare's industry-leading DNS, CDN, and free SSL to make your site faster and more secure. Simple, secure, at-cost domain registration.

Sign up for free
Gen AI apps are built with MongoDB Atlas
Build gen AI apps with an all-in-one modern database: MongoDB Atlas

MongoDB Atlas provides built-in vector search and a flexible document model so developers can build, scale, and run gen AI apps without stitching together multiple databases. From LLM integration to semantic search, Atlas simplifies your AI architecture—and it’s free to get started.

Start Free
1

basE91

basE91 is an advanced method for encoding binary data as ASCII characters. It is similar to UUencode or base64, but is more efficient. The overhead produced by basE91 depends on the input data. It amounts at most to 23% and can range down to 14%.

Downloads: 37 This Week

Last Update: 2015-04-24
See Project
2

MultiMail Offline Reader

MultiMail is an offline mail packet reader for Unix and other systems. It currently supports the Blue Wave, QWK, OMEN, OPX and SOUP formats. It has a full screen, color user interface, built with the curses library.

1 Review

Downloads: 17 This Week

Last Update: 2025-10-30
See Project
3

Diverse Developments

Originally a software partnership between my best friend and myself, Diverse Developments seeks to write "useful stuff", of a very diverse nature... Current projects include a file encoder, and a double-entry accounts package.

Downloads: 0 This Week

Last Update: 2013-02-22
See Project
4

rhizomatics

website tools for lotus domino servers

Downloads: 0 This Week

Last Update: 2014-04-09
See Project
Our Free Plans just got better! | Auth0
With up to 25k MAUs and unlimited Okta connections, our Free Plan lets you focus on what you do best—building great apps.

You asked, we delivered! Auth0 is excited to expand our Free and Paid plans to include more options so you can focus on building, deploying, and scaling applications without having to worry about your security. Auth0 now, thank yourself later.

Try free now