Skip to content
Resumeboard

What an applicant tracking system actually does to your resume

Most advice about "ATS-friendly resumes" is folklore repeated by people who have never read a vendor's documentation. This page is built from what the vendors themselves publish, quoted and linked.

Start with the honest part

No applicant tracking system publishes its parsing rules. There is no spec, no conformance test, and no list of "keywords that pass". What vendors publish is a narrow set of facts: which file types they accept, how large a file may be, which fields the parser fills, and what makes a parse fail. Everything else on the internet is inference.

So that is what this guide does. Each vendor page below separates what the vendor documents from what it does not, and links to the source for every claim.

The four steps, in the order they happen

Every system on this site does the same four things. The differences are in step two and step three.

  1. Upload. You attach a file to a form. This is the only step the vendor fully controls, and it is the step with the hardest documented limits: file type, file size, and whether the file is text or a picture of text.
  2. Text extraction. Something turns your file into a stream of characters. A PDF is a page description, not text, so a parser either reads the text layer or runs optical character recognition. This is where image-only resumes die, and it is the one failure every vendor names.
  3. Field mapping. The text is matched against profile fields: name, email, phone, employer, title, dates. This step is where layout matters, because a parser reading two columns has to guess which column an entry belongs to.
  4. Human review. Every vendor documents that a person is meant to correct what the parser filled. Greenhouse tells candidates to review the parsed data "before submitting all applications"; Oracle's Taleo documentation says the candidate reviews extracted information in the next steps. Nothing a parser produces is treated as authoritative.

The one rule that follows from the documentation

If you remember one thing from this site, remember this: the safest resume is a single-column, text-based document with real section headings and no layout tricks. That is not a style opinion. It is the layout each vendor's own documentation steers you toward, in different words.

What each vendor documents

Every claim on this table is linked to the vendor's own page. Where a vendor documents nothing, the row says so rather than guessing.

Documented facts about resume parsing, by vendor
Vendor Accepts Documents failure modes Publishes a full parser spec
Greenhouse Resume upload with auto-fill on candidate creation. Hard limit: 2.5 MB. Yes, extensively. A named article lists the formatting that breaks a parse, including columns, tables, headers, footers, text boxes, graphics and letter-spaced words. No.
Workday DOCX and PDF, where the PDF "must contain text that's not image-based". Yes. "Resume parsing results can vary based on resume format and order of words." Best results: no images, no image-based styles. Yes — the closest thing in the industry. Workday's own developer documentation for the Resume REST API lists parsing guidelines in full.
Oracle Taleo Depends on the employer's configuration. Resume upload is a block in the application flow, and plain-text paste parsing is available on mobile. Indirectly, through a long list of configuration options the employer sets. Taleo documents parsing as a third-party service delivered "as is". No.
Lever .doc, .docx, .pdf, .txt, up to 10 MB. Partly. Lever documents that parsing populates name, organization and contact details, and that a hosted-site setting can skip email parsing entirely. No.
iCIMS Word or PDF, per iCIMS's own description of the feature. Behaviour is per-customer configuration. Only at the level of the product explainer. iCIMS does not publish parser behaviour per customer. No.

Read a vendor

Greenhouse The most detailed public failure list of any major vendor. Documents a 2.5 MB ceiling, named parsing failure modes, and the languages it can parse. Workday The only vendor that publishes parsing guidelines directly. Its developer documentation lists accepted formats, the fields it returns, and how to write a resume the parser reads cleanly. Oracle Taleo Mostly private label, and it says so plainly. Oracle documents that Taleo parsing is a third-party service delivered as is, and publishes its language support table. Lever The smallest documented surface, and a real file limit. Documents accepted types, a 10 MB limit, and a setting that turns email parsing off. iCIMS A product explainer, not a specification. The most honest page here is about what iCIMS does not tell you, and what that means for you. Lever vs Greenhouse The comparison people actually want. Same question, two very different documentation cultures, side by side.

If you only have a minute

The following is the union of what these vendors actually document, stripped of anything folklore. Nothing here is advice from us; every line traces to a vendor page linked on the vendor pages.

  • Export a text-based PDF or a DOCX. Workday documents those two formats and says a PDF "must contain text that's not image-based". Greenhouse says resumes "uploaded as an image, rather than a document" fail to parse.
  • Keep the file small. Greenhouse stops parsing above 2.5 MB. A resume full of high-resolution images is how people hit that ceiling without noticing.
  • One column. Greenhouse lists "resumes that have a columned layout" among its formatting failures. Workday's published guidelines say to avoid "tabular and column formats".
  • No tables, headers, footers, or text boxes. All three are named, independently, by both vendors that publish failure lists.
  • Use plain section headings. Workday's guidelines ask for proper headings such as EDUCATION and EXPERIENCE, and specifically warn against combining sections under one heading.
  • Put your name at the top, in capitals or initial capitals. Workday's guidelines are unusually specific: start the document with the name, write multi-word names in initial capitals, and never in all lower case.
  • Spell out the employer. Greenhouse documents that company names lacking identifying words such as "Inc.", "Co.", "LTD" or "LLC" cause problems, and that abbreviated titles like "Sr. Account Exec" are hard to resolve against "Senior Account Executive".

What this guide does not claim

We do not rank these systems, and we do not tell you which one to optimise for. A single employer can change parser settings, disable parsing, or run a different vendor on the careers page than the one behind the job posting. Treat everything above as the best available public floor, not a ceiling.

Check your resume against these rules

Resumeboard's ATS check reads your own file and tells you which of these documented rules it breaks, and on which page.

Opens the builder. The check is under Check, on the ATS tab.

Open the ATS check See the print-safe template