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Simple Machines Forum

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Free, open-source PHP forum software with multiple database backends.

751 stars 268 forks last commit first released

Actively maintained

Last commit 3 Sept 2026.

Simple Machines Forum screenshot

Simple Machines Forum (SMF) is an open-source bulletin board software written in PHP. It provides a scalable, feature-rich platform to run online communities with forums, topics, user roles, moderation, and a modular addon system.

Key Features

  • Uses PHP and MySQL, PostgreSQL, or SQLite for data storage.
  • Newly developed template system to simplify customization and theming.
  • Advanced permissions and multi-language support for diverse communities.
  • Package Manager to install/uninstall mods and themes with a few clicks.
  • Rich posting features including WYSIWYG editing, BBCode, spell check, and attachments.
  • Moderation tools and a dedicated moderation center for staff workflows.
  • Attachments, polls, calendars, and RSS/XHTML outputs for rich content and engagement.
  • External integration via SSI to embed recent topics, polls, and news into other websites.
  • Open-source with well-documented source code and community-driven enhancements.

Use Cases

  • Build a public or private forum for a community or business with multi-board structure and granular permissions.
  • Embed forum content into an existing website using SSI to display recent topics, polls, or news.
  • Run a moderated community with attachments, polls, and calendars to coordinate events and discussions.

Limitations and Considerations

Conclusion

SMF offers a mature, lightweight forum solution with a modular extension system and broad database support, suitable for small to mid-sized online communities.

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