How ATS Systems Work: The Complete Guide to Applicant Tracking Systems

You applied to 30 jobs last month and heard nothing. Your resume is strong. Your experience is relevant. So what happened?

Most likely, your resume never reached a human. An Applicant Tracking System (ATS) filtered it out before anyone saw it.

This guide explains exactly how ATS systems work — how they parse your resume, how they score it, and what you can do to make sure yours gets through.

What Is an ATS?

An Applicant Tracking System is software that companies use to manage job applications. Think of it as the gatekeeper between you and the hiring manager.

When you submit a resume through a company's career page, it doesn't go straight to a recruiter. It goes into the ATS, which:

1. Parses your resume — extracts text and categorizes it into fields (name, email, work history, skills, education)
2. Scores your application — compares your resume against the job requirements
3. Ranks you against other applicants — presents a sorted list to recruiters
4. Stores your information — keeps your data on file for future openings

The recruiter sees a dashboard with candidates ranked by relevance. They typically review the top 10-20% of applicants. If the ATS ranked you low, your resume sits in the system unseen.

How Common Are ATS Systems?

Very. Over 98% of Fortune 500 companies use an ATS. But it's not just large enterprises:

• 75% of mid-size companies (100-500 employees) use some form of ATS
• Even small startups increasingly use tools like Greenhouse, Lever, or Ashby
• Government agencies use ATS systems with strict compliance requirements (USAJobs, for example)
• Staffing agencies use ATS to manage candidate pipelines across clients

If you're applying to jobs online, you're almost certainly going through an ATS.

How ATS Parsing Works

Parsing is the first step — the ATS reads your resume file and tries to extract structured data. This is where most resumes first run into trouble.

What the Parser Does

The ATS parser converts your resume document (PDF, DOCX, or plain text) into structured fields:

| Your Resume | Parsed Into | |---|---| | "John Smith" at the top | Name: John Smith | | "john@email.com" | Email: john@email.com | | "Software Engineer at Google, 2022-2025" | Experience: { company: "Google", title: "Software Engineer", dates: "2022-2025" } | | "Python, React, AWS" | Skills: ["Python", "React", "AWS"] | | "BS Computer Science, MIT" | Education: { degree: "BS", field: "Computer Science", school: "MIT" } |

When parsing works correctly, the ATS has a clean, structured profile to work with. When it doesn't, your information gets garbled or lost.

What Breaks Parsing

ATS parsers are good at reading standard resume formats. They struggle with:

Tables and columns. Many parsers read left-to-right, top-to-bottom. A two-column layout can mix your work experience with your skills section, creating nonsensical output.

Text boxes and graphics. Floating text boxes, images, icons, and infographics are often invisible to parsers. That beautiful skills chart with colored bars? The ATS sees nothing.

Headers and footers. Content in document headers/footers is frequently skipped by parsers. Don't put your contact information there.

Non-standard section headings. "Where I've Made an Impact" sounds creative, but the ATS is looking for "Work Experience" or "Professional Experience." Use standard labels.

Unusual file formats. Some systems can't read certain PDF types (especially image-based PDFs from scanning). DOCX is generally the safest format, though modern ATS systems handle most PDFs well.

Special characters and symbols. Bullet characters like ● or ➤ sometimes parse as gibberish. Stick to standard bullet points or dashes.

How to Test Your Resume's Parsability

The simplest test: copy-paste your resume into a plain text editor (Notepad, TextEdit). If the content is readable and in the right order, most ATS systems will parse it correctly. If it's jumbled or missing sections, you have a formatting problem.

Huntly's ATS analysis goes deeper — it scores your resume against real ATS parsing rules and shows you exactly which sections were correctly identified.

ATS Scoring Algorithms

Once your resume is parsed, the ATS scores it against the job posting. This is where keyword matching comes in.

How Scoring Works

The recruiter (or hiring manager) configures the ATS with criteria for each job posting:

• Required keywords: Skills, certifications, or qualifications that candidates must have
• Preferred keywords: Nice-to-have skills that boost your score
• Experience requirements: Minimum years of experience, specific industries, or role types
• Education requirements: Degree level, field of study, specific institutions

The ATS then scores each resume based on how well it matches these criteria. Different systems use different algorithms, but the general approach is:

Exact keyword matching. Does your resume contain the exact phrases from the job posting? "Project management" matches "project management" but might not match "managed projects."

Semantic matching. More advanced systems use AI to understand that "JavaScript" and "JS" mean the same thing, or that "managed a team" relates to "leadership experience." But not all systems are this sophisticated.

Weighted scoring. Not all keywords are equal. Required skills are weighted more heavily than preferred ones. A "must-have" certification that's missing can disqualify you regardless of your other qualifications.

Boolean filtering. Some requirements are pass/fail. If the posting requires a specific license or certification and you don't have it, your score may be zero for that criterion regardless of everything else.

What a Good ATS Score Looks Like

There's no universal ATS score — each system and each job posting is different. But as a general benchmark:

• Below 50%: Your resume is likely getting filtered out
• 50-70%: Might get through depending on the applicant pool
• 70-85%: Strong match — likely to be reviewed by a recruiter
• 85%+: Excellent match — you'll be near the top of the pile

Huntly's ATS scoring engine gives you a score with a full breakdown — you can see which keywords matched, which are missing, and exactly what to fix.

The "Black Hole" Problem

Job seekers call it the "resume black hole" — you submit an application and never hear anything back. This usually happens because:

1. The ATS scored your resume too low for the recruiter to see it
2. The recruiter saw it but your score didn't stand out from the competition
3. The position was filled internally or through referrals (the posting stays up)

Understanding ATS scoring lets you address reason #1, which is the only one entirely within your control.

Common ATS Myths Debunked

There's a lot of bad advice floating around about ATS systems. Let's clear it up.

Myth: "White text" tricks fool ATS systems

The truth: Some people suggest adding invisible white-text keywords to your resume. This used to work in the early 2010s. Modern ATS systems detect hidden text and flag it as manipulation. Some will automatically reject your application. Don't do this.

Myth: You need to use the exact same words as the job posting

The truth: While exact matches help, many modern ATS systems understand synonyms and related terms. "Team leadership" can match "managed a team of 8." That said, using the same phrasing as the job posting is still the safest strategy since not all systems are equally smart.

Myth: PDF resumes don't work with ATS

The truth: Most modern ATS systems parse PDFs without issues. The exception is image-based PDFs (scanned documents) — these contain no extractable text. If your PDF was created from a word processor or resume editor, it works fine.

Myth: ATS systems reject resumes with too many pages

The truth: ATS systems don't care about page count. They parse all the text regardless of length. The one-page rule is a recruiter preference, not an ATS limitation. That said, keep it to 1-2 pages — recruiters do have page preferences.

Myth: You should only apply through company career pages

The truth: Most ATS systems receive applications from multiple sources — career pages, LinkedIn, Indeed, email. The source doesn't affect your ATS score. However, some companies give preference to direct applications, and some job boards reformat your resume during submission (which can cause parsing issues).

Myth: ATS systems are all the same

The truth: There are significant differences between ATS platforms. Workday parses differently than Greenhouse, which parses differently than iCIMS. While you can't optimize for every system individually, following ATS-friendly formatting rules covers the vast majority.

ATS-Friendly Resume Formatting Rules

Follow these rules and your resume will parse correctly on virtually any ATS.

Do

• Use a single-column layout. No sidebars, no two-column designs.
• Use standard section headings. "Work Experience," "Education," "Skills," "Summary." The ATS knows what these mean.
• Use a standard font. Arial, Calibri, Times New Roman, or Garamond. The ATS doesn't care about your font choice, but unusual fonts can cause rendering issues.
• Use reverse chronological order. Most recent job first. ATS systems expect this format.
• Include dates for each role. Month and year format (e.g., "Jan 2023 - Present"). ATS systems use this to calculate experience duration.
• Use standard bullet points. Simple round bullets or dashes. Avoid special characters.
• Save as PDF or DOCX. Both work on modern systems. DOCX is marginally safer for older ATS platforms.
• Put contact info in the document body. Not in headers, footers, or text boxes.

Don't

• Don't use tables for layout. Tables confuse many parsers.
• Don't use text boxes for design elements. They're often invisible to ATS.
• Don't use images or icons for skills ratings, contact info, or section dividers.
• Don't use creative section names. "My Toolkit" instead of "Skills" confuses the parser.
• Don't include a photo. It takes up space and can cause parsing issues.
• Don't use abbreviations without the full form. Write "Search Engine Optimization (SEO)" the first time, then "SEO" afterward.

Top ATS Systems by Company

Different companies use different ATS platforms. Knowing which system a company uses can help you understand how your resume will be processed.

Workday

Used by: Many Fortune 500 companies (Amazon, Walmart, Bank of America, Disney, Netflix)

Workday is one of the most widely used enterprise ATS systems. It's known for:

• Strict parsing — formatting issues are more impactful here
• Long application forms with many required fields
• Limited resume upload flexibility (some implementations prefer manual entry)

Tip: For Workday applications, use the simplest formatting possible and fill out every field manually rather than relying on auto-parsing.

Greenhouse

Used by: Many tech companies and high-growth startups (Airbnb, Pinterest, Stripe, GitLab)

Greenhouse is popular in tech and is generally more resume-friendly:

• Better PDF parsing than many competitors
• Structured scorecards for interviewers
• Candidate-friendly application process

Tip: Greenhouse applications are generally less formatting-sensitive. Focus on content quality and keyword matching.

Lever

Used by: Mid-size tech companies and startups (Netflix for some divisions, Lyft, Shopify)

Lever combines ATS and CRM functionality:

• Good at parsing most resume formats
• Tracks candidates across multiple positions
• Supports sourced candidates (not just applicants)

Tip: Lever handles most formats well. Focus on keyword optimization over formatting.

iCIMS

Used by: Large enterprises across industries (Target, UnitedHealth Group, PepsiCo, IBM)

iCIMS is a major enterprise ATS:

• Strong integration with job boards
• AI-powered candidate matching is improving
• Traditional enterprise UX (longer application processes)

Tip: iCIMS applications often require completing lengthy profile forms. Don't skip optional fields.

Taleo (now Oracle Recruiting Cloud)

Used by: Many government contractors, large corporations, universities

Taleo was one of the original ATS systems:

• Known for lengthy, multi-step applications
• Strict keyword matching (less semantic understanding)
• Still widely used despite its age

Tip: Taleo is the most keyword-literal of the major systems. Match the exact phrasing from the job posting.

How to Find Out Which ATS a Company Uses

Look at the URL when you're on a company's career page:

• *.myworkdayjobs.com → Workday
• boards.greenhouse.io/* → Greenhouse
• jobs.lever.co/* → Lever
• careers-*.icims.com → iCIMS
• *.taleo.net → Taleo

You can also check the page source or look at the careers page subdomain.

How to Check If Your Resume Passes ATS

You don't have to guess. Here are three approaches:

1. The Plain Text Test

Copy your resume content and paste it into a plain text editor. Read through it:

• Is the information in the right order?
• Are all sections present?
• Is it readable?

If yes, basic ATS parsing should work. If sections are jumbled or missing, fix your formatting.

2. The Keyword Comparison

Pull up the job description and your resume side by side. Manually check:

• How many required skills are explicitly mentioned in your resume?
• Are you using the same phrasing as the posting?
• Have you included the job title somewhere in your resume?

Target 80%+ keyword coverage for the best results.

3. Use an ATS Scoring Tool

The most reliable approach. Huntly's ATS optimization tool scores your resume against real ATS parsing and scoring rules. You get:

• An overall ATS compatibility score
• A keyword-by-keyword breakdown showing what matched
• Specific suggestions for missing keywords
• Formatting issue detection
• One-click optimization to fix problems

It takes 30 seconds and removes the guesswork entirely.

Frequently Asked Questions

Do all companies use ATS systems?

Almost all companies above 50 employees use some form of applicant tracking. Very small startups might use email or basic tools like Google Sheets, but as soon as they receive more than a handful of applications per role, they adopt an ATS. Over 98% of Fortune 500 companies use one.

Can I bypass the ATS?

Not directly — if you apply through a company's career page, your resume goes through their ATS. However, you can get around the ATS by getting a referral from someone inside the company. Internal referrals are typically flagged in the ATS and fast-tracked to recruiter review. Networking and direct outreach remain the most effective job search strategies alongside a tailored resume.

Does the ATS reject my resume, or does the recruiter?

Both. The ATS does the initial filtering — if your score is below the threshold, a recruiter may never see your application. But even if you pass the ATS filter, the recruiter makes the final decision. Your resume needs to work for both the algorithm and the human.

How often do ATS systems update their algorithms?

Major ATS platforms release updates regularly, but the core principles of parsing and keyword matching haven't changed dramatically. The trend is toward more AI-powered semantic matching (understanding meaning, not just exact words), but simple keyword matching still dominates most systems. The formatting rules in this guide have been stable for years.

Is it worth paying for ATS optimization tools?

It depends on how many jobs you're applying to. If you're sending out 5+ applications per week, a tool that saves you 30-60 minutes per application pays for itself quickly. Huntly offers ATS scoring for free during our beta period — no credit card required.

What's the difference between ATS score and recruiter appeal?

An ATS-optimized resume gets you past the automated filter. But recruiter appeal is about readability, quantified achievements, and compelling narrative. The best resumes score well on both dimensions. Tailor your resume to nail the keywords, then make sure the content is genuinely compelling for human readers.

Can I have a visually attractive resume that's also ATS-friendly?

Yes, with caveats. You can use clean design elements like subtle color accents, professional fonts, and strategic white space — these don't affect ATS parsing. What you should avoid is complex layouts (multi-column, text boxes, tables) and non-text elements (icons, graphics, images) that confuse parsers. Huntly's resume editor offers professional templates that look great and parse correctly.

What to Do Next

Understanding ATS systems gives you an unfair advantage. Most job seekers submit and hope for the best. You can submit with confidence.

Here's your action plan:

1. Audit your current resume using the plain text test — make sure it parses cleanly
2. Check your formatting against the rules above — fix any table, text box, or header issues
3. Tailor for each application — match your keywords to each job description
4. Score your resume with Huntly's ATS tool to see exactly where you stand
5. Apply strategically — focus on roles where you can hit 70%+ keyword coverage

Want the full picture on tailoring? Read our complete guide to resume tailoring.