An ATS, or applicant tracking system, is the database a company uses to collect applications, pull your resume into a searchable profile, and track where each candidate stands. Workday, Greenhouse, Lever, iCIMS and Taleo are the names you will run into most.
The part most advice gets wrong: the software rarely rejects you by itself. A recruiter does that, usually after running a search or a filter your resume did not show up in. "Passing" an ATS means two things. The parser has to read your file correctly, and the words in it have to match what the recruiter searches for.
What an ATS actually does
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Workday describes its own product as software that supports recruiters through the whole hiring process and acts as a central database for candidate information. The same page lists what it does: pull details from applications into searchable profiles, let recruiters filter those profiles by years of experience or certifications, rank applicants by how well they match the description, and track each candidate's stage.
Parse, search, filter, rank, track. Every one of those is a tool a human uses.
Greenhouse is explicit about the human part. Its documentation for the matching feature states that there is no mechanism that automatically takes action to advance or reject a candidate based on the system's rating; the recruiter must decide to advance, reject or add notes. The data it pulls from a resume is narrow: skills, job titles, years of experience, employment dates and company names.
So: your resume goes in, a parser turns it into fields, and a recruiter with 300 applicants types "Salesforce" or "registered nurse" into a search box and reads the top of the list. If your resume parsed badly or used different words, you are on page six.
What it does not do
It does not read your resume the way a person does. A parser looks for patterns: a name at the top, a section called Experience, a title followed by a company and dates.
It does not fail you for a missing keyword. It simply does not return you when someone searches for it.
One case where software does knock people out on its own: screening questions. "Are you authorized to work in the US?" with a required answer filters an application before anyone sees it. That is a question you answered, not a resume the software judged.
Why keyword match matters
Because search is how recruiters work through volume. They search for the three or four requirements that are hard to train, then read the results.
That means your resume needs the posting's vocabulary, spelled the posting's way. If the ad says "project management" and you wrote "led cross-functional delivery," a search misses you even though you did the thing. Where the field uses both, write the full term and the abbreviation: "certified public accountant (CPA)."
Do not stuff. Pick the 10 to 15 skills the posting actually names, list them in a Skills section, and repeat the important ones inside the bullet points where you used them.
The 8 formatting rules
Greenhouse's support page on failed parses is the most useful document I know for this: a list of what breaks the parser, written by the company that built it. It names multi-column layouts, tables, headers and footers, text boxes, embedded graphics, and image-based uploads as causes, and says Greenhouse cannot parse files over 2.5 MB. Workday's parsing guide gives the same advice in one line: results vary with format, and files without images or image-based styles parse best.
Turn that into rules and you get these eight.
- Single column. Text flows top to bottom, left to right. Two columns get read across, so your skills list ends up spliced into your job titles.
- Standard section headings. Experience, Education, Skills, Certifications. Not "Where I've Made an Impact." The parser is looking for the plain words.
- No tables or text boxes. Not for the header, not for skills, not for dates. Anything inside a box may be skipped entirely.
- Contact details in the body, not the page header. Greenhouse lists name and contact information placed in headers or text boxes as a parse failure. Type them as the first lines of the document.
- Real text, not images. No scanned PDF, no logo, no icon for your phone number, no headshot. If you cannot select the text with your cursor, the parser cannot read it either.
- Send the format the posting asks for. If it says PDF, send PDF; if it says Word, send .docx. When it does not say, either works as long as the PDF is exported from a document, not scanned. Keep the file well under 2 MB.
- Dates as Month YYYY. "Jun 2022 to Mar 2025." Not "Summer 2022," not "2022 to present" with no month, and not the day. Consistent dates are how the system calculates your years of experience.
- Spell job titles out. Greenhouse names abbreviated titles like "Sr. Account Exec" as a problem. Write Senior Account Executive.
None of this makes a resume ugly. Bold headings, a clean font and white space all survive parsing. Layout tricks fail, not typography.
Myth against what really happens
| Myth | What actually happens |
|---|---|
| "The ATS rejects 75 percent of resumes before a human sees them." | The software stores every application. Recruiters search and filter; resumes that do not match a search go unread, which is not the same as rejected. |
| "You need a 90 percent keyword match." | There is no pass mark. Recruiters sort by match and read from the top; you need to be above the candidates who are actually competing with you. |
| "White text keywords in the margin trick the system." | The parser may pick them up, but the recruiter opens the file, selects the text or views it on a dark theme, and sees exactly what you did. |
| "PDFs cannot be read by an ATS." | A text-based PDF is ordinary text to a parser. A scanned PDF is an image, and images are what Greenhouse and Workday both name as the thing that fails. |
| "Fancy design shows creativity." | The recruiter sees your parsed profile first. If columns scrambled it, the design never got a chance. |
| "One resume works for every job." | Vocabulary changes by posting. Ten minutes swapping in the posting's terms is the best edit you can make. |
How to check your resume before you send it
Do three things, in order.
Select all the text in your file and paste it into a plain text editor. That is roughly what a parser sees. If your name, phone and email are not in the first three lines, or your skills appear mid-sentence inside a job description, fix the layout.
Open the posting next to your resume and highlight every requirement, tool and certification it names. Check each appears in your resume in the same words. The ATS resume checker does this comparison for you: upload the PDF or .docx, paste the posting, and it shows which terms are missing and whether the file parsed cleanly.
Then check the length with a word counter. A one-page resume runs about 400 to 600 words, a two-page one about 700 to 1,000. Beyond that you are padding, and padding dilutes the keywords you want the search to find.
Write the cover letter last. It should echo the posting's vocabulary you just collected, and the cover letter generator drafts one from the posting and your resume so the two documents match.
FAQ
Does an ATS automatically reject resumes?
Very rarely, and not for formatting or keywords. Greenhouse states there is no mechanism that automatically advances or rejects a candidate; a recruiter makes that call. The only automatic filters are screening questions with required answers. A resume that parses badly is not rejected, it is just never found.
What is the best resume format for an ATS?
A single-column document with standard headings, contact details typed as text at the top, Month YYYY dates, and no tables, text boxes or images. Save as .docx or as a text-based PDF, whichever the posting asks for, and keep it under 2 MB. Plain does not mean ugly; it means the text flows in reading order.
How do I know if my resume is ATS friendly?
Copy all the text and paste it into a plain text file. If it reads in the right order with your contact details first and your section headings intact, a parser will handle it. Then compare your wording against the posting; if the requirements appear in the same terms, you will show up when a recruiter searches for them.
Do UK, Canadian and Australian employers use ATS software too?
Yes, the same platforms, and the formatting rules do not change. The differences are vocabulary: "CV" in the UK and Australia, day-month-year dates, and local spellings such as "organisation." Match the posting's spelling, because a recruiter searching "organisational" will not find "organizational."
