SquirrelMail is a free, open-source webmail client designed to be lightweight and easy to use. It allows you to access your email account from any web browser, without needing a separate email program like Outlook or Thunderbird installed on your computer. Think of it as a simple, built-in email interface that your hosting provider can install on their servers.

Unlike complex web applications, SquirrelMail focuses on core email functions with a straightforward, no-frills interface. It is built primarily with PHP and uses IMAP and SMTP protocols to communicate with mail servers. This makes it a reliable and resource-efficient choice for many hosting environments.

Key features you'll typically find include:

• Compose, read, reply, and forward emails.
• Organize messages using folders (Inbox, Sent, Drafts).
• Manage an address book for contacts.
• Support for attachments and basic HTML email.

Its primary advantage is simplicity and low system requirements, making it fast even on slower connections. However, its interface can feel dated compared to modern webmail services like Gmail. For users who prioritize function over form and need reliable, browser-based email access, SquirrelMail remains a solid, no-cost solution provided by many web hosts.