SquirrelMail
by SquirrelMail
What SquirrelMail is
SquirrelMail is a free, standards-based webmail package written in PHP for self-hosted use. It provides browser email with built-in PHP support for IMAP and SMTP, plus MIME handling, address books, folder manipulation, and calendar tools. Pages render in HTML 4.0 without requiring JavaScript. An administrator needs a web server running PHP and access to an IMAP4rev1 server. Installations can be adapted with 231 listed plugins across 14 categories. The project is licensed under the GNU General Public License and states that it has no license fees. The download page lists stable version 1.4.22 along with daily stable and development snapshots. A security page identifies a 2025 XSS vulnerability affecting versions through 1.4.23-svn-20250401 and 1.5.2-svn-20250401. SquirrelMail was founded in 1999. It is intended for users whose employer, school, organization, hosting company, or ISP manages the installation, with separate support resources for users and administrators.
Who it suits
It suits organizations that can provide PHP web hosting and an IMAP4rev1 server. End users generally access it through an installation managed by an employer, school, organization, hosting company, or ISP.
What it does well
- Free GPL license with no license fees
- Built-in IMAP and SMTP support
- MIME, address books, and folder tools
- 231 plugins across 14 categories
- Works without requiring JavaScript
What to know first
- Requires self-hosted PHP web server
- Needs access to an IMAP4rev1 server
- Stable download listed as version 1.4.22
- Security page lists a 2025 XSS vulnerability
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| SquirrelMail | GPL licensed · self-hosted webmail; requires a web server with PHP and access to an IMAP server | Free |
As squirrelmail.org lists them, read 12 Oct 2026. The maker's own page has the final word.
Verdict
SquirrelMail offers a no-license-fee webmail package with familiar email functions and extensive plugin customization. It requires administrators to host and connect the software, and the listed security notice deserves attention before deployment.
Facts from SquirrelMail's own pages
- App coverage
- web · squirrelmail.org, 24 Sept 2026
- Browser compatibility
- Its pages render in HTML 4.0 without requiring JavaScript. · squirrelmail.org, 12 Oct 2026
- Calendar tools
- Yes · squirrelmail.org, 24 Sept 2026
- Core features
- The project lists MIME support, address books, and folder manipulation among its email-client features. · squirrelmail.org, 12 Oct 2026
- Customization
- The project lists 231 plugins in 14 categories, which administrators can use to customize installations. · squirrelmail.org, 12 Oct 2026
- Download versions
- The download page lists stable version 1.4.22 and daily stable and development snapshots. · squirrelmail.org, 12 Oct 2026
- Founded
- 1999 · squirrelmail.org, 28 Sept 2026
- Free plan
- Yes · squirrelmail.org, 24 Sept 2026
- Installation requirements
- The administrator manual lists a web server with PHP and access to an IMAP server that supports IMAP4rev1 as requirements. · squirrelmail.org, 12 Oct 2026
- Intended users
- The project describes use by end users whose employer, school, organization, hosting company, or ISP manages the installation. · squirrelmail.org, 12 Oct 2026
- License
- SquirrelMail is licensed under the GNU General Public License, and the project says there are no license fees. · squirrelmail.org, 12 Oct 2026
- Mail protocols
- It includes built-in PHP support for IMAP and SMTP. · squirrelmail.org, 12 Oct 2026
- Security
- The security page lists a 2025 XSS vulnerability affecting versions through 1.4.23-svn-20250401 and 1.5.2-svn-20250401. · squirrelmail.org, 12 Oct 2026
- Support
- The project directs end users and system administrators to different support resources and also links to commercial support. · squirrelmail.org, 12 Oct 2026
- What it does
- SquirrelMail is a standards-based webmail package written in PHP. · squirrelmail.org, 12 Oct 2026
Where SquirrelMail stands on Freedom251
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