An ATS acts as the system of record for hiring. Each vacancy has a pipeline of stages, such as applied, screened, interviewed and offered, and each candidate record holds a CV, notes, messages and history. Most systems also post jobs to boards, send templated emails, schedule interviews and produce reports. Assessment and screening tools typically connect to the ATS so their results appear on the candidate's record.
Because the ATS holds personal data and the history of each hiring decision, it sits at the centre of reporting, audit and data protection compliance. Recruiters work faster when its data is accurate and its stages reflect real activity. When adding screening tools, integration often matters more than features: scores and transcripts should flow back into the ATS so nobody copies information between systems or keeps parallel spreadsheets.