Why Your Resume Gets Rejected Before a Human Sees It
Applicant tracking systems throw out resumes for boring mechanical reasons. Here is what actually trips them, and what is a myth.
Applying for forty jobs and hearing nothing back is common enough that people assume the problem is them. Often the problem is a piece of software that could not read the file properly, and the fixes for that are small and mechanical.
What an ATS actually does
It reads your file as plain text, tries to work out which chunk is your work history and which is your education, and then scores how well your words overlap the posting's words. It is not clever and it is not judging you. It is matching text.
That means every failure is one of two kinds. Either it could not read your document, or it read it fine and did not find the words it was looking for.
The formatting that breaks it
Text inside images is invisible, so a screenshot or a photo of a resume scores zero. Text inside headers and footers is often skipped, which is why putting your phone number up there can leave you unreachable. Multiple columns get read straight across, turning your careful two column layout into scrambled sentences. Tables do the same thing.
A single column, real text, standard section headings like Experience and Education, and a PDF exported from a document rather than scanned. That is the whole checklist, and it covers almost everything.
The keyword part, without the nonsense
The posting is the answer key. If it says forklift, your resume should say forklift, not "warehouse equipment". If it says phlebotomy, say phlebotomy. Use their exact phrasing anywhere it is true of you, and use it in the job description where you did the thing, not in a list at the bottom.
Two things to ignore: pasting white text into the margins, which systems flag now and humans find on sight, and any claim that a specific font or a specific file name gets you past the filter. Neither is real.
How to check before you send
Open your PDF, select all the text, and copy it into a blank note. What you see there is roughly what the system sees. If your name is missing, if the columns have merged into gibberish, or if whole sections vanished, you have found your problem.
Then put your resume and the posting side by side and mark every requirement in the posting that does not appear anywhere in your resume. That list is your edit for the next ten minutes, and it is usually shorter than people expect.