Roundcube
Hosting

Roundcube is the webmail client almost everyone has used at some point, even if they didn't know its name. If you've logged into webmail through your hosting control panel in the last fifteen years, you've probably seen Roundcube. It's the default on most cPanel and Plesk setups, including ours, and the standalone version is what people install when they want a customer-facing webmail interface that doesn't look like a control panel.

What works well: the three-pane layout is intuitive for anyone who's used Outlook or Thunderbird, IMAP support is solid, the plug-in ecosystem covers two-factor auth, calendar, contacts, and message encryption, and the project has been in steady development since 2008. New releases ship regularly, security fixes are timely, and the codebase is clean enough that we've been able to debug obscure customer issues without too much pain.

What's annoying: the default theme has aged. Roundcube ships with the Larry skin and a newer Elastic skin, and Elastic is much better, but the install defaults still trip some people up. The plug-in directory is scattered across GitHub repos and the project's own site, so finding well-maintained plug-ins takes some hunting. And the calendar plug-in, while good, requires a bit of setup work to integrate with CalDAV servers.

"Roundcube is the boring webmail client that just works. Twenty years from now, when most of today's mail apps have been acquired and shut down, Roundcube will still be here, still rendering messages in three panes, still letting you ignore the latest AI-driven email assistant. That is high praise."

Mark McNeece, Founder, 365i Hosting

On hosting: Roundcube runs cleanly on our shared hosting from £5.99/mo. PHP 8.5 is fine, the MySQL footprint is tiny (preferences and address books only), and a typical install for a single user or small team uses well under 100MB of disk space, ignoring the IMAP store itself which lives on the mail server. We've never had a Roundcube install hit unlimited LVE resources, even on busy customer-facing deployments.

The thing to be careful with is session handling. Roundcube stores active sessions in the database by default, and on a busy install the sessions table can grow. The garbage collection cron job is included with our installer, but it's worth checking that it's actually running every few months, especially after upgrades.

If you want a customer-facing webmail interface (a membership site, a paid mail service, or a domain reseller setup), Roundcube is the right pick over building one yourself. Set the Elastic skin as default, configure the plug-ins for two-factor auth and password change, and brand the login page with your own logo. Most of the customisation is in config files and CSS overrides rather than core code edits, which keeps upgrades clean.

For most 365i customers who just want webmail, you don't need to install Roundcube manually because it's already available through the hosting control panel. The one-click installer is for people who specifically want a standalone, customisable, separately-branded Roundcube of their own.