What Is an ATS and Why Should You Care?

An Applicant Tracking System (ATS) is software that employers use to manage the hiring process. It collects, scans, sorts, and ranks resumes before a human recruiter ever sees them. Companies like Taleo, Workday, Greenhouse, Lever, and iCIMS dominate the market, and over 98% of Fortune 500 companies use some form of ATS.

Here is the uncomfortable truth: studies suggest that up to 75% of resumes are rejected by ATS before reaching a recruiter. That means three out of four applicants are eliminated by software, not people. If you have ever applied to dozens of jobs without hearing back, there is a good chance an ATS filtered you out.

How an ATS Actually Works

Understanding the mechanics helps you beat the system:

Parsing - The ATS extracts text from your resume and attempts to identify sections like work experience, education, skills, and contact information.
Categorization - It maps the extracted data into structured fields in a database.
Keyword Matching - The system compares your resume content against the job description, looking for relevant keywords and phrases.
Ranking - Candidates are scored and ranked based on how closely their resume matches the job requirements.
Filtering - Recruiters set minimum thresholds. Resumes below the cutoff never get reviewed.

Why Most Resumes Get Rejected

Resumes fail ATS screening for several common reasons:

Missing keywords: The resume does not contain the specific terms from the job description.
Poor formatting: Tables, text boxes, headers, footers, and graphics confuse the parser.
Wrong file format: Some ATS struggle with certain file types.
Unconventional section headings: Creative headers like “Where I’ve Made an Impact” instead of “Work Experience” cause parsing failures.
Lack of relevant content: The resume is too generic and does not align with the specific role.

Keyword Optimization Strategies

Keywords are the foundation of ATS optimization. Here is how to use them effectively:

Match the Job Description

Read the job posting carefully and identify:

Hard skills: Specific tools, technologies, certifications (e.g., “Python”, “PMP”, “Salesforce”)
Soft skills: Qualities mentioned repeatedly (e.g., “cross-functional collaboration”, “leadership”)
Industry terms: Jargon specific to the field (e.g., “agile methodology”, “GAAP compliance”)

Use Exact Phrasing

If the job description says “project management,” use that exact phrase rather than just “managed projects.” ATS software often performs literal string matching.

Include Variations

Use both the acronym and the full term: “Search Engine Optimization (SEO)” covers both bases. Some systems search for one but not the other.

Place Keywords Strategically

Include them in your Skills section for easy parsing.
Weave them naturally into your Work Experience bullet points.
Add them to your Summary or Professional Profile at the top.

Avoid Keyword Stuffing

Do not list keywords in white text or repeat them unnaturally. Modern ATS systems can detect this, and recruiters who eventually read your resume will notice.

Formatting Do’s and Don’ts

Formatting is where most candidates unknowingly sabotage themselves.

Do’s

Use a clean, single-column layout with clear section breaks.
Use standard fonts like Arial, Calibri, Times New Roman, or Garamond.
Use standard bullet points (round or square) for lists.
Keep font size between 10-12pt for body text and 14-16pt for headings.
Use bold and italics sparingly for emphasis. Most ATS can handle these.
Left-align all text for consistent parsing.

Don’ts

Avoid tables and columns: ATS parsers read left to right, top to bottom. Multi-column layouts scramble your content.
Avoid headers and footers: Many ATS systems cannot read content placed in header or footer areas. Critical information like your name or contact details may be lost.
Avoid images, logos, and icons: ATS cannot read images. That beautiful skill-level bar chart is invisible to the software.
Avoid text boxes: Content inside text boxes is often skipped entirely.
Avoid fancy dividers or design elements: Lines, shapes, and decorative elements can cause parsing errors.
Avoid uncommon characters: Stick to standard punctuation and avoid special symbols.

File Format Best Practices: PDF vs. DOCX

This is one of the most debated topics in resume optimization.

DOCX

Pros: Universally parsed by all ATS systems. The safest choice.
Cons: Formatting may shift slightly across different versions of Word.

PDF

Pros: Preserves formatting exactly as intended. Looks professional.
Cons: Older ATS systems struggle to parse PDFs. Some strip out text entirely.

Our Recommendation

Submit DOCX unless the job posting specifically requests PDF. If a company uses a modern ATS (most do in 2026), PDF is fine. When in doubt, DOCX is the safer bet. Always ensure your PDF is text-based (created from a word processor), not a scanned image.

Section Ordering and Naming Conventions

ATS systems expect a conventional resume structure. Use these standard section headings:

Contact Information (name, phone, email, LinkedIn, location)
Summary or Professional Summary
Work Experience or Professional Experience
Education
Skills or Technical Skills
Certifications (if applicable)
Awards or Honors (if applicable)
Volunteer Experience (if applicable)

Avoid creative alternatives. “Career Journey” might sound appealing, but “Work Experience” is what the ATS is programmed to recognize.

How to Use Tailor’s AI Scanner to Check ATS Compatibility

Tailor offers an AI-powered ATS scanner that helps you optimize your resume before you submit it. Here is how to use it:

Upload your resume to Tailor’s platform in PDF or DOCX format.
Paste the job description you are targeting.
Run the ATS scan - Tailor’s AI analyzes your resume against the job description.
Review your score - You will see a compatibility percentage and detailed feedback.
Follow the recommendations - Tailor highlights missing keywords, formatting issues, and section problems.
Re-scan after making changes to confirm improvement.

Tailor uses the same parsing logic as major ATS platforms, so if your resume passes Tailor’s scanner, it is highly likely to pass real-world ATS screening.

Common ATS Myths Debunked

Myth 1: “ATS automatically rejects my resume”

Reality: ATS does not reject resumes on its own. It ranks and filters them based on criteria set by the recruiter. A low score means a recruiter is less likely to see you, but the system itself is not making a yes/no decision in most cases.

Myth 2: “I need to stuff my resume with keywords”

Reality: Keyword stuffing is counterproductive. Modern ATS and recruiters can both detect it. Focus on natural, contextual use of relevant terms.

Myth 3: “A fancy design will make me stand out”

Reality: A visually stunning resume may actually hurt you. ATS parsers struggle with complex designs. Save the creative formatting for portfolios or industries where ATS is not used.

Myth 4: “PDF files always get rejected”

Reality: Most modern ATS systems parse PDFs just fine. The issue arises with image-based PDFs (scans) or PDFs with heavy graphical elements. A clean, text-based PDF works in the vast majority of cases.

Myth 5: “One resume works for every job”

Reality: This is perhaps the biggest mistake. Every job description has unique keywords and requirements. Tailoring your resume for each application dramatically increases your ATS score.

Myth 6: “ATS only looks at keywords”

Reality: Advanced systems also evaluate work experience duration, job title relevance, education level, and career progression. Keywords matter, but they are not everything.

Final Checklist

Before you submit your next application, run through this quick checklist:

[ ] Resume is in DOCX or clean PDF format
[ ] No tables, text boxes, images, or header/footer content
[ ] Standard section headings are used
[ ] Keywords from the job description are included naturally
[ ] Both acronyms and full terms are present
[ ] Single-column, clean layout with standard fonts
[ ] Contact information is in the body of the document, not the header
[ ] Resume has been scanned with Tailor’s ATS checker

Optimizing for ATS does not mean writing a robotic resume. It means presenting your qualifications in a format that both machines and humans can read effectively. With the right approach, you can dramatically increase the number of interviews you land.

Ready to check your resume’s ATS compatibility? Try Tailor’s free ATS scanner and get your score in seconds.