What Is ATS? How an Applicant Tracking System Works

Header photo by Haberdoedas on Unsplash. A stock photo, not a screenshot of AceDraft or of any ATS.

What is ATS? In hiring, ATS stands for applicant tracking system: the software an employer uses to collect job applications, store them and track each applicant until a decision is made. That's the short answer to "what is an applicant tracking system". If you searched "what is ATS in resume", you're really asking about your own file, and I come to that near the end.

First, the limit. I build a resume tool, AceDraft. I don't build an ATS, and I've never had access to an employer's ATS. I've never logged in to one on the employer's side.

So what follows about how these systems work comes from three public sources, each with a date, plus a few plain explanations of my own that I label as mine. Every employer sets its system up differently, and I can't see any of those setups.

I also haven't pushed a resume through any employer's ATS to see what came out, so you won't find a description here of how Workday, Taleo, Greenhouse, iCIMS or any other named system handles a file. If you'd rather check my product's claims on a known file than take my word for them: check in presale page for our demo resume and you can verify our claims in the opensource tool we have mentioned there.

One thing this post won't do is re-argue the frightening stories about ATSs throwing resumes away. I did that separately in ATS myths, checked, and I'll point there when one of those claims comes up.

Key takeaways

• An applicant tracking system is hiring software that keeps each applicant in one record, which Coursera (updated 10 June 2026) calls a candidate profile.
• Employers configure their own systems. Setups differ.
• You control two inputs: the resume you upload and the answers you type into the form. The rest sits on the employer's side, out of view.
• Limitation: I have no access to any employer's ATS, and AceDraft's free scan is my own scoring against one pasted job description.

What is ATS, and what does ATS stand for?

Wikipedia's article on applicant tracking systems (last edited 14 September 2026) describes a software application for the electronic handling of recruitment and hiring, and says it is very similar to a CRM system, only built for recruitment tracking.

A CRM is the contact database a sales team uses to keep track of customers: who each one is, and what's meant to happen next. Swap customers for applicants and you've got the basic idea.

I find that comparison more useful than the formal definition, because it tells you what the thing is for. It's a filing system with a to-do list attached.

The Indeed Career Guide (updated 16 June 2026) gives a narrower definition: recruitment software employers use to collect, sort and rank the resumes they receive. Wikipedia describes the whole hiring process. Indeed describes what happens to the resumes. Neither tells you how a particular employer has set theirs up.

The letters are crowded, by the way. When I pulled Google India's results for "ats full form" through OpenSEO on 29 September 2026, only one of the eight organic results was about applicant tracking, and it was in eighth place. The rest were about the Anti-Terrorism Squad or some other meaning of the letters. If you came here for the police unit, this is the wrong page, and I apologise.

What is an applicant tracking system used for, and who uses it?

Going by Wikipedia's article (last edited 14 September 2026), an applicant tracking system is used for tasks that run from sourcing candidates and posting a job to scheduling interviews and reporting. I've grouped its list by when each item happens; the grouping is mine and the items are Wikipedia's.

• Before anyone applies: sourcing candidates and posting jobs.
• When an application comes in, parsing the resume.
• Sorting what has arrived, which covers searching and filtering candidate databases, and ranking and rating candidates.
• Everything after that: managing and tracking applicants, scheduling interviews, automated emails and reminders, and reporting and analytics.

Coursera's guide (updated 10 June 2026) adds a few things staff can do inside one. It says an ATS lets employees leave notes about candidates, schedule interviews and message candidates. Coursera also says many ATSs double as job boards.

That's a long menu, and an employer doesn't have to order all of it. Which parts are switched on, and how each one is set up, is the employer's choice. From outside you can't tell which ones a given company uses. Neither can I.

On who uses one, I'm not giving you a figure. I haven't found a count of employers using an ATS that comes with a date and a method I could check, so there's no percentage anywhere in this post. The definitions themselves answer the question well enough: Indeed describes software employers use, and Coursera describes employees working inside it.

As for why, my reading of Wikipedia's list is that the point is keeping every step of hiring attached to one record, the way a CRM keeps a sales team's customers in one place. None of my sources says that outright. It's an inference from the list.

What happens to my resume after I click apply?

After you apply through an ATS, the system collects your materials, such as your resume and cover letter, and creates a candidate profile, according to Coursera's guide (updated 10 June 2026). That profile is the record every later step in this post attaches to.

Here is the order I'd expect things to happen in, pieced together from my three sources. It's a sketch of the general shape. A real employer's process may skip steps, add its own, or run two at once.

1. You submit your resume, and maybe a cover letter, through a form.
2. The ATS collects them and creates your candidate profile (Coursera).
3. The resume is parsed, meaning details are pulled out of the file and stored. Parsing resumes is on Wikipedia's list of uses.
4. If the employer added questions to the form, your answers are stored too. None of my three sources covers this step. I've put it here because the answers have to go somewhere.
5. Search and sort. Staff can search, filter, rank and rate the profiles (Wikipedia). Coursera says algorithms oftentimes compare resumes with the job description.
6. Each profile moves through the employer's own stages, with notes, interview scheduling and messages along the way (Wikipedia and Coursera).
7. A decision gets made. None of my sources says the software makes the final hiring call, and all three describe people working in the system, so I'd expect a person to be involved.

Coursera's point about job boards matters here: the page you applied on may itself belong to an ATS. From the applicant's side, I can't tell you which pages do.

The step I'd pay most attention to is the second one. If the form asks you to type in details, like your phone number or past job titles, those go into the same record as far as I can tell. So I'd give the form as much care as the file.

How does an ATS read my resume?

An ATS reads a resume by parsing it, which Wikipedia (last edited 14 September 2026) lists among its uses. Parsing is the general word for software pulling pieces out of a document, such as your name, email address, job titles and dates, so they can be stored in fields and searched later.

That's as far as my sources go. None of them says how accurately a particular system parses, or what it does with a two-column layout. I haven't tested one either. Each system is built by a vendor and configured by an employer, and I can't see the code or the settings.

I can describe the view from my side of the fence. AceDraft's free scan takes a resume PDF up to 10 MB and compares it with a job description you paste. That's my code reading your file.

It says nothing about how an employer's code reads the same file. I'd distrust any scanner that claims otherwise, including a future version of mine.

The format questions, such as whether columns, tables or PDFs cause trouble, are where I've seen the strongest claims with the least evidence behind them. I've gone through the ones I could check in the myths post linked above, so I won't repeat them here.

There's one check you can run yourself, with no ATS involved at all. Open your resume PDF, select all the text, copy it and paste it into a plain notepad. If it comes out in the order you wrote it, with your headings where you expect them, at least one piece of software read the file the way you meant.

If it comes out scrambled, I'd fix that before worrying about anything else in this post.

It's a crude test, and I know it. A notepad isn't an ATS. It's still more evidence than a guess.

What are screening or knockout questions?

Screening questions are the extra questions some employers add to an application form, such as your notice period or whether you hold a particular qualification. A knockout question is the name for a screening question where the employer has decided that one answer rules an applicant out for that job. None of my three sources covers either term, so that's my plain explanation, not a sourced one, and I can't tell you how any system handles the answers.

What I can say is who sets them: the employer. Which questions appear, and what happens to your answers, depends on that employer's setup, and you can't see it from the applicant's side of the form.

So my advice is short. Answer every question truthfully and exactly. If a form asks for your notice period, give the real one. A false answer stays false after you press submit.

How do recruiters search and filter applications in an ATS?

Recruiters and other hiring staff can search, filter, rank and rate the applications stored in an ATS: Wikipedia's article (last edited 14 September 2026) lists "searching and filtering candidate databases" and "ranking and rating candidates" among the use cases. How a given employer uses those tools is not described in any of my sources.

Two of my sources go a step further, and each deserves its own attribution.

Coursera's guide (updated 10 June 2026) says that oftentimes, algorithms compare resumes to the job description and rank candidates by overlapping keywords. That's Coursera's description of something it says happens often. Whether it happens at the company you're applying to depends on how that employer set its system up.

The Indeed Career Guide (updated 16 June 2026) says an ATS uses keywords the employer specifies to categorise and rank resumes. It then says resumes with the fewest matching keywords, or not formatted for an ATS, "are often removed from consideration". That line is exactly the kind of claim I examined in ATS myths, checked, so read that before you treat it as settled. Indeed attaches no figure to it, and I'm not adding one.

My practical takeaway is modest. Whatever search or ranking an employer runs, it works on what's in your profile, and the part of that profile you wrote is your resume. The words on the page are yours to choose, as long as each one is true.

Author's take. I built a keyword comparison into AceDraft's scan, so I know a little about how fiddly this is. An earlier post of mine recorded scan runs where the skills bars returned nothing, and two of the Score Breakdown bars still say "coming soon".

If my own comparison has gaps like that, I'm not going to assume anyone else's is flawless. I'd write for the posting and the person reading it, and stop short of tuning a resume to a guess about software I've never seen.

Does a person still read my resume?

Whether a person reads your resume depends on the employer's process, and I can't see inside any employer's process to tell you. What I can show is that my three sources describe an ATS as a tool with people working in it.

Coursera's list, quoted above, describes employees doing things inside an ATS, with the software holding the record. Wikipedia's list adds managing and tracking applicants.

None of the three sources says the software makes the final hiring decision. Indeed writes about ranking, and about resumes being removed from consideration, which I dealt with above. It doesn't describe a system hiring anyone.

Here's what I can't tell you: how many applications a person opens at any company, or how far down a ranked list anyone reads. I don't have that number. If someone quotes you one, ask where it came from and when it was measured.

So the honest answer is an unsatisfying one. My sources describe people working inside the system and never describe the software hiring anyone, so my reading is that a person is involved somewhere. When they look at your resume, and how much of it, is set by the employer and invisible from outside. I'd write the resume for that person and make sure the file's text copies out cleanly, which covers both readers without guessing at either.

What can I actually control as a job seeker?

As a job seeker you control two things that go into an ATS: the resume you upload and the answers you type into the form. The employer controls the rest, from which features are switched on to who looks at what.

That's also my answer to "what is an ATS resume". The Indeed Career Guide has a page titled "How To Write an ATS Resume" (updated 16 June 2026). My own definition is simpler: your true skills and experience, written in the words the posting uses, in a PDF whose text you've checked copies out cleanly. I don't think there's a secret layer beyond that.

The table follows one application through the stages my sources describe. The last column is the part I'd want you to take seriously, because it's where every outside tool, mine included, runs out.

Where I'd spend the effort, part by part:

• The skills list. Use the posting's names for tools you really use. I've written a separate guide to your skills section.
• The top of the page, if you write a summary. There are samples in resume summary examples, and if you're early in your career, resume objective examples too.
• No job history yet? Then projects, education and volunteering carry the page, which is what I cover in a resume without work experience.
• The file: a PDF whose text survives the copy-and-paste test from earlier.
• Every form answer.

If you want to build it somewhere free, AceDraft's guest editor needs no sign-up. Its sections run from Basics and Professional Summary down to Projects and References, with Skills, Education and My Experience in between.

After you press Save, the progress screen offers a free ATS-ready plain-text PDF: no sign-up, no payment, no watermark, your resume as written. On the web it opens your browser's print dialog, where you pick Save as PDF.

"ATS-ready" is my product's name for that export. I haven't run the file through any employer's ATS, so I can't promise how one reads it. There's more on the free tier in what 'free' covers.

How do I check my resume before I apply?

You can check a resume against one job description with AceDraft's free ATS scan, but no outside tool can check it against a particular employer's ATS. AceDraft has no access to any employer's system, and neither do I.

The scan needs a resume PDF, up to 10 MB, and a job description you paste in. A target job title is optional. Results come back in about 30 seconds and aren't gated behind an email. Signed out, you get 15 scans a day; signed in, free or paying, scans are unlimited.

The results show an ATS score, Keywords Matched out of the number it identified, Keywords Missing from the job description, Readability, a Score Breakdown and a list of top issues and fixes. The score and top issues are free. A free account adds a deeper AI quality review and saves your scans, and line-by-line fixes come with the paid export.

Heads up. The scan is AceDraft's own scoring against one pasted job description. It isn't any employer's ATS, and nobody has checked its score against Workday, Greenhouse or any other named system.

Inside the Score Breakdown there are three scored bars: Hard Skills, Job Title Alignment and Soft Skills. Each compares your resume with terms found in the posting. A bar shows "not scored" instead of 0% when it couldn't be measured, for example Job Title Alignment when you gave no job title.

Formatting and Content Quality say "coming soon", which means they aren't scored today. I haven't tested how accurate the skills bars are, and an earlier post recorded runs where they returned nothing. I'd rather you knew that before you trusted a number from them.

I've written more on why a scanner can't see inside an employer's ATS, and on how to read your ATS score row by row. For a tour of every ATS question the product itself answers, see AceDraft's ATS FAQ.

My own routine before an application is short. Copy-paste test on the PDF. Scan against the posting. Add the missing words that are true of me and ignore the ones that aren't. Then one slow read of the whole page, as if I were the person on the other side.

What haven't I tested?

I haven't tested any of this inside a real employer's ATS, and that's the biggest gap in the post. Here's the full list, so you can weigh the rest for what it is.

• No employer-side access. Every description of how an ATS works comes from Wikipedia, Coursera and Indeed, read on 29 September 2026, and those pages can change.
• No named-ATS behaviour. I haven't submitted a resume through Workday, Taleo, Greenhouse, iCIMS, Lever or any other system, so I can't say how any of them parses, sorts or screens.
• Screening and knockout questions: explained in general terms only, since none of my three sources covers them.
• I found no dated, checkable count of how many employers use an ATS, so I haven't given one.
• AceDraft's scan has untested skills-bar accuracy, with empty runs recorded in an earlier post, and Formatting and Content Quality aren't scored yet.
• The free ATS-ready plain-text PDF hasn't been through any employer's ATS.
• No outcome data of any kind. AceDraft is pre-launch: no users, no usage data and no reviews.

For the part you can check yourself on a known file: check in presale page for our demo resume and you can verify our claims in the opensource tool we have mentioned there.

That tool is ATS Screener. It's open source and simulates Workday, Oracle Taleo, iCIMS, Greenhouse, Lever and SAP SuccessFactors, and it isn't affiliated with any of them. A simulation is still somebody's model of a system, the same caveat I put on my own scan. I haven't recorded any scores from it, and I won't quote one.

Use this post if you want a neutral picture of what an ATS is and where your application goes inside one, with every source dated and the unknowns marked as unknown.

Skip it if you need to know how one named system, at one named employer, will handle your resume. I can't tell you that, and I don't think any tool outside that employer can.

Sources

• Wikipedia, Applicant tracking system. Last edited 14 September 2026; read 29 September 2026.
• Coursera Staff, What Is an Applicant Tracking System?. Updated 10 June 2026; read 29 September 2026.
• Indeed Career Guide, How To Write an ATS Resume. Updated 16 June 2026; read 29 September 2026.
• OpenSEO keyword data for "what is ats" and "what is an applicant tracking system" (checked 27 September 2026) and "what is ats in resume" (checked 29 September 2026); Google India SERP data for "ats full form", checked 29 September 2026.
• AceDraft, AceDraft presale page. Read 29 September 2026.