An Applicant Tracking System (ATS) is software that companies use to collect, sort, and filter resumes before a recruiter reviews them. Most mid-size and large companies use one — Workday, Greenhouse, Lever, and iCIMS are the most common. The system parses your resume into a structured record, and if it can't parse a section correctly, that information effectively doesn't exist to the recruiter who searches or filters candidates.
What actually breaks an ATS parse
Most advice about ATS is vague or outdated. Here's what concretely causes parsing failures, based on how these systems are built:
- —Multi-column layouts — many parsers read left-to-right across the page, scrambling a two-column resume into nonsense
- —Text inside images, icons, or graphics — nothing in an image gets extracted
- —Tables used for layout — the same column-reading problem as above
- —Section headers that aren't standard — 'Where I've Worked' won't be recognized as Experience the way 'Experience' or 'Work History' will
- —Contact info in a header/footer — some parsers skip headers and footers entirely
- —Non-standard fonts or heavy styling — increases the odds of character-level parsing errors
What an ATS check should actually tell you
A useful ATS check does more than say "pass" or "fail." It should tell you which sections it found, which keywords from your field are present or missing, and whether your resume's length and structure are working for or against you. That's what Career Copilot's free checker returns — a score, not a guess.
Fixing an ATS problem without over-formatting your resume
The fix is rarely "add more keywords." It's usually structural: use standard section headers, keep to a single column, avoid tables and text boxes, and make sure your contact information sits in the body of the document, not a header. None of this requires making your resume look plain — it just means the visual design and the underlying document structure need to agree with each other.
Free vs. paid ATS checkers
Most free ATS checkers online do a keyword count and stop there. Career Copilot's free analysis also flags missing standard sections and gives specific, resume-referenced suggestions — and it's the same engine used for job-specific matching once you have an account, so the score you get here isn't a one-off gimmick.
Common ATS myths worth retiring
A few claims circulate constantly and don't hold up. "ATS software rejects resumes with any graphics" — false; it rejects text trapped inside graphics, a subtle but important difference from icons used decoratively next to real text. "You need to match the job description word-for-word" — false; you need the same skills expressed in standard terminology, not an exact string match, which reads as keyword stuffing to a human reviewer even when it helps a naive parser. "PDFs never work with ATS" — false for any modern platform; the layout inside the PDF is what matters, not the file format itself.
Frequently asked questions
Does every company use an ATS?
Nearly all mid-size and large companies do — Workday, Greenhouse, Lever, and iCIMS are the most common platforms. Smaller companies and startups are more likely to have a human read every resume directly, but formatting a resume for ATS compatibility never hurts a human-reviewed application.
Can an ATS actually reject a resume automatically?
It depends on the employer's configuration. Some ATS platforms only sort and rank candidates for a recruiter to review manually; others apply automatic keyword-match filters that can screen out a resume before anyone sees it. Because you can't know which setup a given employer uses, it's safest to assume parsing quality matters either way.
Do ATS checkers actually simulate the real system?
A good one approximates the same parsing logic — checking section headers, layout structure, and text extraction the way common ATS platforms do — rather than guessing. No free tool has access to every employer's exact configuration, so treat the result as a strong signal, not a guaranteed pass/fail.
Will a PDF or a Word doc parse better?
Modern ATS platforms generally handle both formats well as long as the underlying structure is simple — single column, standard section headers, real text rather than text-in-an-image. PDF is the more common recommendation because it preserves formatting consistently across systems, but a cleanly structured Word doc parses just as reliably.
For a deeper technical walkthrough of the extraction process itself, see How ATS Parsing Actually Works.