An Applicant Tracking System (ATS) is a software application that enables the electronic handling of recruitement and hiring needs. An ATS can be implemented or accessed online at enterprise or small business levels, depending on the needs of the organization. Free and open-source ATS software is also available. The principal function of an ATS is to provide a central location and database for a company's recruitement efforts. It is built to better assist management of resumes anad applicant information. In many cases they filter applications automatically based on the given criteria such as keywords, skills, former employers, years of experience, schools attended and so on.