How screening systems read a resume
What an ATS does with your resume
An applicant tracking system turns your document into data: it extracts your name, your jobs, your dates and your skills and stores them so a recruiter can search and filter. The first step is plain text extraction, which is why a resume that looks perfect on screen can arrive scrambled: text boxes, tables, multiple columns, headers and footers or icons used as labels may be read in the wrong order or not at all.
Most systems do not reject people automatically for a missing keyword. They rank and filter, and a recruiter decides. What matters is that the system finds the right fields and that the words the recruiter searches for appear in them.
What this scanner checks, and what it does not
It checks 13 points that depend on your data: contact details, professional title, summary, complete jobs with dates in reverse order, bullet points per job and their length, figures in the results, skills, education, odd symbols and total length. With a job posting it also counts how many of the posting's most repeated terms your resume shares.
It does not open your file to judge the design, and it does not know which system a company uses. If you want a full opinion on content and wording, use the resume review tool; if you want to rewrite your resume for one posting, use the tailoring tool.
Myths worth dropping
A resume does not need to be ugly to be readable: a clean one-column layout with real headings looks professional and parses well. Hiding keywords in white text does not help: many systems show the raw text, and recruiters see it as deception. And copying the posting word for word is not the point; use its terms only where they describe something you did.