Alternatives to SeaMonkey

Classic internet suite combining a browser, email, feed reader, IRC client and HTML editor. The listings below can replace it for an important use case. Each note says what changes if you switch.

Replacements

Listings that take over the same core job as SeaMonkey.

  • Vivaldi

    A Chromium browser for people who want tab stacks, split screen and a mail client in the same window.

    FreeProprietaryWindowsmacOSLinux

    Vivaldi keeps browsing, mail, calendar and a feed reader in one window on a current Chromium engine, but has no IRC client or HTML editor and is not fully open source.

  • Firefox

    The main browser not built on Chromium, with tracking protection turned on by default.

    FreeOpen sourceWindowsmacOSLinuxAndroidiOS

    Firefox provides a current, actively maintained open-source engine with strong extension support, but mail, feeds, IRC and page editing would need separate programs.

  • Pale Moon

    Independent Firefox fork with the classic interface and XUL extension support.

    FreeOpen sourceWindowsmacOSLinux

    Pale Moon keeps a classic interface and XUL extensions on the pre-Quantum Gecko engine, but it is a browser only, without mail, IRC or an HTML editor.

  • Basilisk

    Non-Chromium browser from the Pale Moon ecosystem that keeps XUL extensions.

    FreeOpen sourceWindowsmacOSLinux

    Basilisk runs classic XUL extensions from the Pale Moon ecosystem as a standalone browser, and its small team means security fixes and web compatibility lag.

  • Waterfox

    A Firefox build with telemetry stripped out, ad blocking and encrypted DNS turned on from the start.

    FreeOpen sourceWindowsmacOSLinux

    Waterfox tracks current Firefox with telemetry removed and ad blocking on by default, but it is a standalone browser with no mail, feed or editor tools.

Also worth comparing

These listings name SeaMonkey as their own alternative, so the relationship runs both ways.

  • Otter Browser

    Use a configurable browser inspired by classic Opera.

    FreeOpen sourceWindowsLinux

    SeaMonkey is a classic MPL-2.0 internet suite combining browser, email, feed reader, IRC client and HTML editor on an older Firefox codebase, with a macOS build.

Similar software

Related functionality, not a direct replacement.