The debate is older than most of the systems people apply to. Both DOCX and text-based PDFs can parse cleanly. Image-only PDFs, heavy tables, and two-column layouts break more often than the file extension itself.
What most ATS actually do
Extract text and attempt to map it into fields: experience, skills, education, contact.
Prefer clean linear structure over visual design.
Fail more often on multi-column layouts, text boxes, headers/footers that hide content, and scanned or image PDFs.
Still leave the final ranking and shortlist decision to a human in most real hiring workflows.
DOCX advantages
Native editable structure. Many portals and older parsers handle Word well.
Easier for you to keep a single-column, standard-heading version.
Some systems autofill more accurately from .docx than from complex PDFs.
Simple to revise between applications without export friction.
PDF advantages (when done right)
Locks layout so fonts and spacing stay consistent for the human reader.
Widely accepted; many companies explicitly request PDF.
Text-based (not scanned) PDFs with selectable text parse fine in modern systems.
Avoid exporting from a design tool that turns text into outlines or images.
What matters more than the extension
Single column, standard section names (Experience, Education, Skills).
No critical content in tables, sidebars, headers, or graphics.
Keywords and titles that match the job description where they are true for you.
After upload, check the autofilled fields and fix anything the parser misread.
Athena’s role
Athena ATS scores your resume against the job description you paste and rewrites for that posting.
First rewrite is free. Founding Beta is $8/mo or $59/yr. No interview guarantee.