CiviCRM is an open-source constituent relationship management (CRM) system designed for non-profits to track interactions with constituents, collect donations and membership fees, manage events, and send broadcast emails. It integrates with content management systems and has features for contributions, memberships, events, and email marketing. While missing some reporting capabilities and ease of use features, CiviCRM is used by many large non-profits and can be installed for free but requires technical skills for setup and maintenance. Resources are available online to help evaluate if CiviCRM meets an organization's needs.