SquirrelMail is a free, open-source PHP webmail client with IMAP support. Learn its history, features, and current maintenance status.
SquirrelMail is a free, open-source webmail client written in PHP that lets users read, compose, and manage email through a web browser via the IMAP protocol. It was created in 1999 by brothers Luke and Nathan Ehresman with the explicit goal of running well on low-end servers and rendering in simple browsers without requiring JavaScript.
For much of the 2000s and early 2010s, SquirrelMail was one of the most widely deployed webmail clients, bundled by default into many shared web hosting control panels and Linux distribution repositories. It is licensed under the GNU General Public License version 2 or later, and the project has never operated as a commercial company, having always been maintained by volunteer contributors.
SquirrelMail's core feature set reflects its origins as a lightweight, dependency-free webmail client: full IMAP support for connecting to standard mail servers, a plugin architecture that lets administrators add features like address books, filters, and spam controls, multi-language interface translations, and a minimal-footprint HTML interface that avoids JavaScript so it works in basic browsers and over slow connections. Its plugin ecosystem, built by the community over two decades, extends the base client with calendar tools, PGP encryption support, and various administrative utilities.
SquirrelMail is entirely free and open source; there is no paid tier, subscription, or commercial license. Organizations self-host SquirrelMail on their own web and mail servers, incurring only their own infrastructure costs. Because the project has no company or vendor behind it, there is no official paid support offering, though third-party consultants and hosting providers sometimes offer support as a service.
Development has slowed dramatically since 2011; the project continues through unofficial SVN snapshots rather than regular numbered releases, and many consider it largely unmaintained.
Yes, SquirrelMail is completely free and open source under the GNU General Public License.
SquirrelMail was created in 1999 by brothers Luke and Nathan Ehresman.
Because known security vulnerabilities remain unpatched in official releases, security-conscious users are generally advised to migrate to actively maintained alternatives like Roundcube.
SquirrelMail connects to mail servers using the IMAP protocol.
No, it was specifically designed to work without JavaScript so it renders in minimal browsers.
Yes, through its plugin architecture and theme system administrators can extend and customize the interface.
Roundcube has become the more common default webmail client on modern hosting control panels.