An applicant tracking system (ATS) is a software application that enables the electronic handling of recruitment needs. An ATS can be implemented or accessed online on an enterprise or small business level, depending on the needs of the company and there is also free and open source ATS software 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.