How ATS Software Actually Works (And Why Most Resumes Fail)
What an Applicant Tracking System reads, how it scores, and the seven mistakes that get your resume thrown out before a human ever sees it.
An Applicant Tracking System is a database, not a brain. It ingests your resume as text, splits it into sections, and runs string matches against the job description's required and preferred keywords. That's most of it. No semantic understanding. No reading between lines.
What the ATS sees
Your beautiful PDF gets flattened to text. Multi-column layouts get scrambled. Tables get destroyed. Images and icons disappear entirely. The recruiter sees what the parser produced, which is often a garbled mess that looks nothing like the document you sent.
The scoring shortcut
Most ATS scoring boils down to keyword overlap with the job description, weighted by section. Skills section keyword = high weight. Same keyword in a buried bullet = lower weight. Repetition past two or three times yields no extra points.
Seven mistakes that kill your score
- Two-column layouts. Parsers read left-to-right, top-to-bottom. A two-column resume reads as nonsense.
- Tables for skill grids. Cells get serialized in unpredictable order.
- Headers and footers. Many parsers skip them entirely. Don't put your phone number there.
- Fancy fonts and ligatures. Smart quotes, em dashes, and ligatures often render as
?or get dropped. - "Hard worker" / "team player" filler. Zero keyword value. Worse: signals weakness to the human reviewer who eventually reads it.
- No quantification. "Improved performance" beats nothing, but loses to "cut p99 latency 62%".
- Mismatched dates. Inconsistent formats trigger date-parser failures, which downgrades your structure score.
What to do instead
Single column. Plain text headings. ASCII characters. Action verbs first. Numbers in every other bullet. Keywords from the JD, used naturally. That's the whole game.