CiviCRM

CiviCRM is an open source CRM built by a community of contributors and supporters, and coordinated by the Core Team. CiviCRM is web-based software used by a diverse range of organisations, particularly not-for-profit organizations (nonprofits and civic sector organizations). CiviCRM offers a complete feature set out of the box and can integrate with your website.
CiviCRM is created and used by a global community of tens of thousands of individuals and organisations. Our vision is that 'all organisations – regardless of their size, budget, or focus – have access to an amazing CRM to engage their contacts and achieve their missions'. Our roadmap outlines the shorter term goals we are implementing to acheive our vision. Source: https://civicrm.org/about