How ATS Systems Work — and Why Most Resumes Fail Them

What is an Applicant Tracking System?

An Applicant Tracking System (ATS) is software used by employers to collect, sort, and filter job applications. Many employers, especially larger ones, use ATS software.

Before your resume reaches a recruiter, it is usually collected and organised by the system. Depending on how the employer has set it up, recruiters may search, filter or rank applications, so a resume that is hard to parse or lacks the right keywords can be easy to overlook.

How ATS software scores your resume

Different ATS platforms use slightly different algorithms, but most rely on the same basic idea: keyword matching. Recruiters search and filter by keywords, and some systems also compare your resume with the job description and show a match score. How this works varies by product and by how the employer has configured it.

Here's what the software typically looks for:

• ✓Exact keyword matches: The ATS looks for the specific words and phrases used in the job posting. "Project management" and "managing projects" are NOT the same thing to an ATS.
• ✓Job title alignment: Your current or most recent job title is heavily weighted. If the posting says "Senior Marketing Manager" and your title is "Marketing Lead", you may score poorly.
• ✓Skills section parsing: ATS software specifically scans for a designated skills section. Skills buried inside job descriptions may be missed.
• ✓Education requirements: Degree level and field of study are parsed and matched against requirements. Formatting matters here — unconventional layouts can confuse the parser.
• ✓Years of experience: Many systems extract years of experience from employment dates and match against stated minimums.

Why most resumes fail the ATS test

The most common reason resumes get filtered out isn't bad experience — it's poor keyword matching and formatting problems. Here are the biggest offenders:

1. Generic resumes with no tailoring

Sending the same resume to every job is the single biggest mistake job seekers make. A generic resume will match the exact keywords of exactly zero job descriptions. Read our guide on why you should tailor your resume for every job to understand just how much this matters.

2. Tables, columns, and fancy formatting

Two-column resume templates look great to a human but are invisible to many ATS parsers. The software reads left-to-right, top-to-bottom — so a two-column layout mixes your skills section with your work history, creating gibberish that can't be parsed correctly.

Headers, text boxes, images, and icons cause the same problem. Stick to a clean, single-column format for any job you're applying to through an online portal.

3. Non-standard section headings

ATS software is trained to look for section titles like “Work Experience”, “Education”, and “Skills”. If you get creative and call your experience section “My Professional Journey” or “Career Highlights”, the ATS may not recognise it — and your experience may go uncounted.

4. Keyword synonyms and abbreviations

ATS systems are more literal than you might expect. If the job posting says “JavaScript” but your resume says “JS”, there may be no match. Similarly, “Search Engine Optimisation” won't match “SEO” in all systems. It's safest to include both the abbreviation and the full term.

5. Submitting as PDF (sometimes)

Older ATS software struggles to parse PDF files, especially those created from design tools like Canva or InDesign. While most modern systems handle PDFs well, if you're unsure, submitting a DOCX file is the safer choice.

7 fixes that will dramatically improve your ATS score

The bottom line

The ATS is not the enemy — it's a filter that rewards relevance. The good news is that once you understand what it's looking for, beating it comes down to a systematic process of matching your language to the job description.

The downside? Doing this manually for every application can take 20–30 minutes per job. That's why we built ImprovedCV — paste your resume and the job description, and our AI rewrites your resume to improve your keyword match in about 30 seconds.