What is an Applicant Tracking System?
An Applicant Tracking System (ATS) is software that sits between you and the hiring manager. When you submit your resume through a company's career page or a job board like LinkedIn, Indeed, or Glassdoor, it almost never goes straight to a person. Instead, the ATS receives it, breaks it apart, extracts information, and decides whether you're worth a recruiter's time.
Think of it as a gatekeeper with a checklist. The ATS scans your resume for specific keywords, job titles, years of experience, education, and certifications. It then assigns your application a relevance score. If you score high enough, your resume gets forwarded to a recruiter. If not, it sits in a database—possibly forever.
The numbers are staggering: 98% of Fortune 500 companies use ATS software. So do 66% of large organizations and 35% of small businesses. Popular systems include Workday, Greenhouse, Lever, iCIMS, and Taleo. Each one works slightly differently, but they all follow the same core logic: parse, match, rank.
Studies show that 75% of qualified candidates are rejected by ATS before a recruiter ever sees their resume. Not because they're unqualified—because their resume wasn't formatted or worded in a way the software could understand.
That means three out of four people who could do the job never get a chance to prove it. If you've been applying to dozens of jobs and hearing nothing back, this is almost certainly part of the problem.
How ATS Actually Reads Your Resume
Understanding what happens behind the scenes is the first step to beating the system. Here's the process, step by step:
Parsing: Breaking Your Resume Apart
The ATS starts by extracting raw text from your file. It tries to identify and categorize information into structured fields: your name, email, phone number, work history, education, and skills. This is where most resumes start failing.
If your resume uses a two-column layout, the parser might read across both columns and mash content together. If you put your contact info in a header or footer, many ATS systems skip it entirely—meaning your phone number and email never make it into the system. Tables, text boxes, and graphics are even worse: the parser either ignores them or scrambles the content into gibberish.
A resume that looks beautiful in a PDF viewer can be completely unreadable to an ATS. This is the single biggest reason qualified candidates get filtered out.
Keyword Matching: The Scoring Engine
Once the ATS has extracted your information, it compares your resume against the job description. It's looking for specific keywords: job titles, technical skills, certifications, tools, and industry terms.
Here's what most people don't realize: ATS keyword matching is often literal. If the job description says "project management" and your resume says "managed projects," some systems won't count that as a match. If the job requires "JavaScript" and you only wrote "JS," you might miss that keyword entirely. The system isn't trying to understand your experience—it's pattern-matching text strings.
More advanced ATS platforms (like Greenhouse or Lever) use some degree of semantic matching, but even they work best when you use the exact language from the job posting. The safest approach is always to mirror the terminology the employer uses.
Ranking: Who Gets Through
After parsing and matching, the ATS ranks all applicants by relevance. The recruiter then reviews the top candidates—typically the top 25 to 50 resumes out of hundreds. Your goal isn't perfection; it's to land in that top tier.
Some ATS platforms also check for "knockout questions"—things like required certifications, minimum years of experience, or work authorization. If you fail one of these, your resume is automatically rejected regardless of how strong the rest of your profile is. Always answer screening questions honestly and completely.
Resume Formatting That Works With ATS (Not Against It)
The most common reason resumes fail ATS isn't missing keywords—it's bad formatting. A resume that looks creative and polished to a human can be completely unreadable to software. Here's how to format your resume so the ATS can actually parse it:
Use a Single-Column Layout
Two-column and sidebar layouts are popular in modern resume templates, but they're a nightmare for ATS parsers. The software reads top-to-bottom, left-to-right. With two columns, it often reads across both columns on the same line, creating nonsensical combinations of unrelated text. Stick to a simple, single-column format. It might feel boring, but it works.
Stick to Standard Section Headings
ATS is trained to recognize conventional headings like "Work Experience," "Education," "Skills," and "Certifications." When you get creative with headings like "My Professional Journey" or "What I Bring to the Table," the system may not know where to put that content. It might categorize your work experience as "other" or skip it entirely. Use the boring, standard labels.
Avoid Graphics, Images, and Icons
Skill bars, pie charts, star ratings, headshot photos, and decorative icons all look great on screen—but ATS can't read any of them. If your Python proficiency is represented by a 4-out-of-5 star rating, the ATS sees nothing. If your contact information is embedded in a graphic header, it's invisible. Every piece of important information must be in plain text.
Put Contact Info in the Body, Not Headers/Footers
Many people put their name, email, and phone number in the document header. The problem? Several major ATS platforms (including older versions of Taleo and iCIMS) strip headers and footers during parsing. Your resume might go into the system with no contact information at all. Put your name and contact details at the very top of the main document body instead.
Skip Tables and Text Boxes
Tables are especially problematic. Even a simple two-column table (dates on the left, descriptions on the right) can cause parsers to scramble the content or lose information entirely. Text boxes have the same issue—content inside them may be extracted out of order or ignored. Use plain text with bullet points and line breaks instead.
Choose the Right File Format
The safest format is .docx (Microsoft Word). Every ATS can parse it reliably. Most modern ATS also handle PDFs well, but some older systems still struggle with them—especially PDFs created from design tools like Canva or InDesign, which often embed text as images or use non-standard encoding. If the job posting doesn't specify a format, go with .docx. If it explicitly asks for PDF, submit a PDF—but keep the formatting simple.
Use Standard Fonts
Stick to widely supported fonts: Arial, Calibri, Times New Roman, Helvetica, or Georgia. Decorative or uncommon fonts can cause character rendering issues during parsing. Font size should be 10-12pt for body text and 14-16pt for headings. Don't go smaller than 10pt—some parsers struggle with tiny text.
Keyword Optimization: The Art of Speaking the ATS's Language
Even with perfect formatting, your resume will score low if it doesn't contain the right keywords. Here's how to identify and use them effectively—without turning your resume into a keyword-stuffed mess.
How to Find the Right Keywords
Start with the job description. Read it carefully—not just the requirements section, but the entire posting. Pay attention to:
- Job titles and variations (e.g., "Software Engineer," "Software Developer")
- Required technical skills and tools (e.g., "Python," "Salesforce," "Tableau")
- Certifications (e.g., "PMP," "AWS Certified," "CPA")
- Industry-specific terms (e.g., "Agile methodology," "HIPAA compliance")
- Soft skills mentioned explicitly (e.g., "cross-functional collaboration")
Then look at 3-5 similar job postings from other companies. If the same terms keep appearing across multiple postings, those are high-value keywords for your industry and role.
Where to Place Keywords
Don't just dump keywords into your skills section. The most effective approach is to weave them naturally throughout your resume:
In your summary/objective: Your opening statement should include 2-3 of the most important keywords. Instead of "Experienced professional seeking a challenging role," write "Senior Data Analyst with 5 years of experience in SQL, Python, and business intelligence using Tableau."
In your work experience: This is where keywords carry the most weight. Describe your accomplishments using the exact terminology from the job description. "Led cross-functional Agile team of 8 engineers" hits three keywords at once.
In a dedicated skills section: Create a clear "Skills" or "Core Competencies" section with a bulleted list of your most relevant hard skills. This gives the ATS an easy target for keyword extraction.
The Acronym Trap
This catches more people than you'd expect. If you write "SEO" but the job description says "Search Engine Optimization," you might miss the match. If you write "User Experience" but they're searching for "UX," same problem.
The solution is simple: include both forms. Write "Search Engine Optimization (SEO)" the first time you use it. Write "User Experience (UX) Design." This costs you nothing and ensures you match regardless of how the ATS searches.
Tailoring vs. Keyword Stuffing
There's a critical difference between tailoring your resume (good) and keyword stuffing (bad). Tailoring means adjusting the language and emphasis of your genuine experience to match each job description. Keyword stuffing means cramming in terms you can't back up, hiding white text with keywords, or listing every technology you've ever heard of.
Modern ATS platforms can detect hidden text and over-repetition. And even if they can't, remember: the ATS is just the first gate. A recruiter reviews the top resumes, and they'll immediately notice if your resume is a keyword salad that doesn't tell a coherent story. You need to pass both the machine and the human.
Why (and How) to Tailor Your Resume for Every Application
This is the advice everyone gives but nobody wants to follow: you need to customize your resume for every single job you apply to. Yes, every one. Here's why it matters and how to do it without losing your mind.
A generic resume might hit 40-50% of the keywords for any given job. A tailored resume can hit 70-85%. That difference is often the gap between getting filtered out and getting a call. When you consider that the average job posting receives 250 applications, even a small improvement in ATS score can move you from the middle of the pack to the top.
The 15-Minute Tailoring Method
You don't need to rewrite your resume from scratch for every job. Start with a strong base resume, then spend 15 minutes customizing it for each application:
- Read the job description carefully. Highlight every skill, tool, qualification, and requirement mentioned.
- Compare to your resume. Check which of those highlighted terms already appear in your resume. For the ones that don't but that you genuinely have experience with, add them.
- Adjust your summary. Rewrite 1-2 sentences in your professional summary to reflect the specific role. Mention the job title and 2-3 key requirements.
- Reorder your skills. Put the most relevant skills for this specific job first in your skills section.
- Tweak 2-3 bullet points. Adjust the language in your most recent role to mirror the job posting's terminology. If they say "stakeholder management," use that phrase instead of "working with clients."
That's it. Fifteen minutes per application, and you've potentially doubled your chances of getting through the ATS. Over time, you'll build a library of bullet point variations that makes this process even faster.
Before & After: ATS-Optimized Resume
Let's look at a concrete example. Same person, same experience—but completely different results with an ATS:
Before (Low ATS Score)
Creative Problem Solver
↑ Uncommon title — ATS can't match this to "Software Engineer"
Professional Journey
↑ Non-standard heading — ATS may skip this section
• Worked on stuff with JS
↑ Vague + abbreviation only — misses "JavaScript" keyword
• Helped the team
↑ No specifics, no numbers, no keywords
After (High ATS Score)
Software Engineer
↑ Standard title, matches job posting exactly
Work Experience
↑ Standard heading the ATS recognizes
• Developed web applications using JavaScript (JS), React, and Node.js
↑ Full name + abbreviation, specific technologies
• Led team of 5 engineers, increasing delivery speed by 40%
↑ Quantified result, leadership keyword
The Mistakes That Silently Kill Your Applications
Most ATS failures aren't dramatic. You won't get an error message or a rejection email explaining what went wrong. Your resume just quietly disappears into a database. Here are the most common culprits:
The "Beautiful Template" Trap
Those sleek resume templates from Canva, Etsy, or Behance with infographics, skill bars, and creative layouts? They're designed to impress humans browsing portfolios—not ATS software. When a parser encounters a two-column layout with a sidebar, icons, and rating systems, it often extracts gibberish or misses entire sections. The irony is that the more effort you put into making your resume visually impressive, the worse it may perform with ATS.
Save the creative template for situations where you're handing your resume directly to a person (networking events, career fairs, direct emails). For online applications, use a clean, simple format.
The One-Resume-Fits-All Approach
Sending the same resume to every job is the most common reason for low ATS scores. Even within the same role (say, "Marketing Manager"), different companies use different terminology. One posting might emphasize "content marketing" and "SEO," while another focuses on "demand generation" and "marketing automation." Your resume can't score well on keywords it doesn't contain.
Typos and Inconsistencies
A human recruiter might forgive a typo. An ATS won't. If you misspell "management" as "managment" or "JavaScript" as "Java Script," the keyword match fails silently. Inconsistent formatting is also a problem—if you write "2020 - 2023" for one job and "2018 to 2020" for another, some parsers may struggle to extract your timeline correctly. Be meticulous and consistent.
Missing Job Title Alignment
If the job posting is for a "Software Engineer" but your resume says "Application Developer," you might not match—even if the roles are identical. Many ATS systems weight job title matches heavily. You can't lie about your actual title, but you can add context: "Application Developer (Software Engineer)" or mention the target role's title in your summary statement.
Advanced ATS Strategies Most Guides Don't Tell You
Use the Job Description as Your Outline
Here's a technique that works remarkably well: take the requirements section of the job description and use it as the skeleton for your experience bullet points. If the posting lists "Experience managing cross-functional teams," one of your bullet points should describe a time you managed a cross-functional team—using that exact phrase. You're not copying the job description; you're translating your experience into the employer's language.
Front-Load Your Most Recent Role
ATS systems (and recruiters) pay the most attention to your most recent position. If your current role is only loosely related to the job you're applying for, spend extra time crafting those bullet points to emphasize transferable skills. Your most recent 2-3 roles should have the most detail; older positions can be brief.
Don't Forget About the Human
Here's the thing everyone forgets: passing the ATS is only half the battle. Once your resume makes it through, a recruiter will spend an average of 7.4 seconds scanning it. That means your resume needs to be simultaneously ATS-optimized AND easy for a human to read quickly. Use clear headings, concise bullet points, and quantified achievements that jump off the page. "Increased quarterly revenue by $2.4M through targeted email campaigns" catches a recruiter's eye in a way that "Responsible for email marketing" never will.
Apply Early
This is more of a practical tip than an ATS trick, but it matters: many companies review applications in batches, and some recruiters start screening as soon as the first resumes come in. If you apply within the first 48 hours of a job posting going live, you're competing against a smaller pool. Set up job alerts on LinkedIn and Indeed so you can move quickly when relevant positions appear.
How CareerCheck Helps You Beat the ATS
You can do all of this manually—read job descriptions, compare keywords, check formatting. Or you can let CareerCheck do the analysis for you. Upload your resume, paste a job description, and get an instant ATS compatibility score with specific, actionable feedback:
- Keyword Gap Analysis: See exactly which critical keywords from the job description are missing from your resume
- Formatting Check: Identify ATS-unfriendly elements that could cause parsing errors
- Skill Matching: Compare your skills against the job requirements with a detailed match report
- Tailored Resume Generation: Auto-generate an ATS-optimized version of your resume for the specific job
Frequently Asked Questions
What is a good ATS score?
Most ATS systems don't show candidates a score directly, but as a benchmark: your resume should match at least 70-80% of the keywords in the job description. Below 50%, your chances drop dramatically. You can check your match rate using CareerCheck's free analysis—just upload your resume and paste the job description.
Should I use a PDF or Word document?
.docx is the safest choice. Every ATS can parse it reliably. Most modern ATS platforms also handle PDFs well, but there are edge cases: PDFs exported from design tools like Canva or InDesign sometimes embed text as images, making them unreadable. If the job posting specifically asks for PDF, submit a PDF—but create it by exporting from Word or Google Docs, not from a design tool. When in doubt, .docx.
Can I game the ATS with hidden keywords?
Some people try hiding keywords in white text or tiny font. Don't do this. Many modern ATS platforms can detect hidden text, and even if they can't, the recruiter reviewing your resume might. Some ATS actually show recruiters a "parsed" version that strips formatting, making hidden text visible. It's an easy way to get your application thrown out and your name flagged. Focus on genuine keyword optimization instead.
How often should I update my resume?
You should tailor your resume for every job application. That doesn't mean rewriting it from scratch each time—it means adjusting your summary, reordering skills, and tweaking bullet points to match the specific job description. Keep a "master resume" with all your experiences and accomplishments, then customize from that base for each application. It takes 10-15 minutes per job and significantly improves your ATS score.
Do all companies use ATS?
Not all, but the vast majority do. Nearly 100% of Fortune 500 companies, 66% of large organizations, and 35% of small businesses use ATS software. The general rule: if you're applying through a company's career page or a job board (LinkedIn, Indeed, Glassdoor), assume an ATS is screening your application. The only common exceptions are very small companies where the hiring manager reads every email directly, or when you submit your resume through a personal connection who hands it directly to the decision-maker.
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