An applicant tracking system (ATS) is a software application that enables the electronic handling of recruitment 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. An ATS is very similar to customer relationship management (CRM) systems, but are designed for recruitment tracking purposes. In many cases they filter applications automatically based on given criteria such as keywords, skills, former employers, years of experience and schools attended. This has caused many to adapt resume optimization techniques similar to those used in search engine optimization when creating and formatting their résumé.