"Make sure your resume is ATS-friendly" is common advice that rarely comes with an explanation of what an ATS actually does. Here's the practical version.
What an ATS actually is
An applicant tracking system is software companies use to collect, store, and search resumes before a human ever opens one. When you submit a resume through a company's careers page, it almost always goes into an ATS first — not directly to a recruiter's inbox. The ATS extracts text from your file (parsing), stores it as searchable data, and often lets a recruiter filter or search candidates by keyword before reading a single resume by hand.
The risk isn't that the ATS "rejects" you for bad formatting in some dramatic sense — it's quieter than that. If the parser can't correctly extract your job titles, dates, or skills because of how the document is laid out, that information effectively doesn't exist in the system, even though it's sitting right there on the page a human would read fine.
What actually trips up a parser
- Multi-column layouts. A parser generally reads left to right, top to bottom. A two-column resume can get read completely out of order — a bit of your left column, then a bit of your right column, interleaved in a way that scrambles the actual content.
- Tables. Similar problem — content inside table cells doesn't always extract in a sensible reading order.
- Text inside images or graphics. If your name, contact info, or skills are part of a designed graphic rather than real selectable text, most parsers can't read it at all. Try selecting the text on your own resume with your cursor — if you can't highlight it, a parser probably can't read it either.
- Headers and footers. Some ATS software skips header/footer regions of a page entirely — a bad place to put your contact information if you want it reliably captured.
- Unusual section headings. "Where I've Been" is a fine, personable heading for a human reader. A parser looking for something that maps to "Experience" may not recognize it. Standard headings (Experience, Education, Skills) get correctly categorized far more reliably.
What doesn't actually matter as much as people think
Font choice, color accents on headings, and reasonable use of bold/italic don't meaningfully hurt ATS parsing — modern systems handle those fine. The formatting choices that matter are structural: single column vs. multi-column, real text vs. text-in-an-image, tables vs. plain paragraphs. A resume can look clean and modern and still be entirely single-column and parser-safe underneath.
Building one
Our Resume Builder is built around exactly this: single-column layout, standard section headings, real selectable text throughout, no tables or graphics anywhere in the output — the structural choices above, handled automatically rather than left for you to get right by hand. You fill in your details, see a live preview as you type, and download the result as PDF or Word.
Try it here: Resume Builder.