Applicant Tracking System

A large company often receives several hundred applications for a single job posting. Managing these by hand in folders would hardly be feasible. That’s why almost all larger employers use software that takes care of exactly this: the Applicant Tracking System, or ATS for short. It accepts applications, stores them in a database, and keeps track of which step of the process each applicant is currently in. You can picture it as a digital filing cabinet with a built-in assistant. The assistant sorts, searches, and reminds the HR department of open tasks.

The invisible bouncer before the job interview

For applicants, the ATS matters because it is often the first authority to ever see an application at all. Not infrequently, the software has a say in which documents a human later reads carefully. Anyone who submits an application as a beautifully designed graphic file risks the system being unable to capture the text at all. The resume then appears empty in the database, even though its content is strong.

For companies, it’s about time and legal certainty. An ATS documents who made which decision and when. This is important if a rejected applicant later suspects discrimination. In addition, the software shortens the time to hire, and HR departments watch this particular metric very closely.

It becomes critical when the system adopts patterns from the past. A well-known example: in 2018, Amazon halted a self-developed selection tool because it systematically rated women worse. The reason was that it had learned from past hiring decisions in which predominantly men had been hired. Such biases remain the biggest criticism of automated pre-selection to this day.

From PDF to sorted candidate list

The first step is called parsing: the software breaks down the uploaded resume into individual fields. It recognizes name, education, work experience, and skills, and writes them into fixed columns of the database. Only this makes applications comparable in the first place. With unusual layouts featuring columns, tables, or graphics, information is frequently lost in the process.

This is followed by matching against the job posting. Simple systems work with keywords: if the posting says “Python” and the resume also says “Python,” points are awarded. More modern systems use language models, that is, programs that compare meaning rather than mere word matches. They can then also recognize that “data analysis with Pandas” is content-wise related to Python.

In the end, a ranking or a score per applicant is produced. A common misconception is that an ATS independently deletes applications. In most cases, it merely sorts them, and the HR department still sees all incoming applications. However, hard exclusion filters do exist as well, for example in the case of a missing work permit or a mandatory degree requirement.

Where you practically encounter ATS software

Every time you don’t apply via email on a company website but instead fill out a form and click on fields like “years of work experience,” there’s an ATS behind it. Common products are called Workday, SAP SuccessFactors, Greenhouse, or Personio. The message “Your application has been received,” appearing just seconds after submission, also comes automatically from this system.

In advice guides, the term usually appears as a warning: the resume should be “ATS-friendly.” What’s meant is a simple layout, a searchable text file, and terms that also appear in the job posting. The advice is legitimate, but it is often exaggerated.

In business news, on the other hand, the focus is on regulation. The EU’s AI Act classifies software for applicant selection as a high-risk application. Companies must then prove that their systems are tested and traceable. In New York City, a requirement has been in effect since 2023 to have such tools audited annually for bias.