OpenCATS

OpenCATS is a free, open-source applicant tracking system and recruitment CRM for recruiters, staffing agencies, and hiring teams. It manages the recruiting process from job posting and candidate application through candidate selection and submission.

The system keeps candidates, applicants, and job postings in one place and tracks them across the hiring workflow. It runs on a PHP and MySQL stack, and end-user and installation documentation is published on the project documentation site.

OpenCATS is a long-running open-source project, first published on GitHub in 2009. It is built to be self-hosted on infrastructure you control rather than offered as a hosted service, which suits agencies that want to keep candidate data in house.