What Is an ATS? Applicant Tracking Systems Explained
How an ATS works
When you submit a résumé, the ATS parses it into structured fields (name, work history, skills, education), then matches that data against the job requirements. Recruiters search and filter the database by keyword, years of experience, title, and location. If your résumé is hard to parse or lacks the right keywords, it ranks low or never surfaces.
Why résumés get rejected by an ATS
- Missing keywords — the skills and titles in the job description aren't in your résumé.
- Unparseable formatting — tables, columns, text boxes, images, or headers/footers confuse the parser.
- Non-standard section headings — creative labels instead of "Experience," "Education," "Skills."
- No measurable results — vague duties instead of quantified achievements.
How to get past an ATS
Mirror the exact keywords in the job posting, use standard section headings, keep a single-column layout with real selectable text, start bullets with action verbs, and quantify your impact. You can score any résumé against a job description with Applio's free ATS checker.
Frequently asked questions
Do all companies use an ATS?
Most mid-size and large employers use an ATS, and the majority of Fortune 500 companies do. Even many small companies use one through their job-board or recruiting software.
Can an ATS read PDFs?
Modern ATS software reads text-based PDFs well. Avoid scanned or image-based PDFs, and make sure your text is selectable rather than an image.
How do I know if my résumé is ATS-friendly?
Paste your résumé and the job description into a free ATS checker. It scores keyword match, formatting, and completeness and shows exactly what to fix.