The complete guide to ATS-ready resumes
Most job seekers have never seen the inside of an Applicant Tracking System. This guide explains how ATS parsers actually work, which formatting choices break them, how to identify and place the right keywords, and how to test your CV before you hit send.
What an ATS actually does
Applicant Tracking Systems were originally built to store and route applications — a digital filing cabinet. Today they do much more. Modern ATS platforms used by mid-size and enterprise employers (Greenhouse, Lever, Workday, iCIMS, Taleo) run a three-phase pipeline on every application they receive:
- Parse — the system converts your CV document (PDF, DOCX, RTF) into structured data: name, contact details, each work experience with employer, title, dates, and bullet text; education entries; skills. Parsers use a combination of rule-based boundary detection and machine-learning entity extraction.
- Score — the parsed CV is scored against the job description using keyword matching, often supplemented by semantic similarity (embedding cosine distance). Some platforms also score completeness and readability.
- Route — based on that score, the application is either advanced to a recruiter queue, moved to a "review later" bucket, or (in high-volume settings) automatically rejected. Most employers never see applications that score below an internal threshold.
The implication is stark: a CV that looks great printed on paper can score near-zero if the parser misreads it. Understanding the parse step is the single highest-leverage thing you can do before applying.
There are roughly three generations of ATS in production today. Legacy systems (often Taleo deployments in large enterprises) parse with basic regex rules and are easily confused by columns, graphics, and non-standard fonts. Mid-generation systems (Greenhouse, Lever) use smarter parsers but still expect conventional single-column structure. The newest systems (Workday 2023+, Ashby) use ML-based parsers and handle PDFs more gracefully — but not perfectly.
Because you rarely know which generation of ATS is in use, the safe strategy is to format for the lowest common denominator: a single-column DOCX with clear section headers and no decorative elements. That document will parse correctly on every system, old or new.
The 10 formatting rules that matter
Of the dozens of formatting choices you make when writing a CV, these ten have a direct, measurable impact on ATS parse accuracy. The rest are aesthetics.
1. Single column, always
Multi-column layouts are the most common source of parse failures. When a parser reads a two-column document linearly, the left and right columns interleave — so a job title from the left column appears next to a skill from the right column. The parser assigns both to the wrong fields. Use one column.
2. Standard section headers
Parsers detect section boundaries by matching header text against a known vocabulary. "Work Experience", "Employment History", "Professional Experience" all reliably trigger the experience parser. Creative alternatives like "Where I've been" or "My story" do not. Use conventional headers.
3. No text boxes or graphics
Text inside DOCX text boxes is stored in a separate XML element that most parsers skip. Skills listed in a visual icon grid are completely invisible to ATS. Every piece of information must appear in the main document flow.
4. No tables for core content
Tables for layout (e.g., two-column skills section) cause the same interleaving problem as multi-column layouts. Tables can be used sparingly for structured comparison data (e.g., a publications list) but not for primary experience or skills content.
5. Standard fonts at readable sizes
Stick to system fonts — Calibri, Arial, Times New Roman, Georgia — or widely available Google Fonts. Unusual fonts that are not embedded correctly in the DOCX file will fall back to a system default, sometimes breaking character spacing. Body text at 10–12pt, headers at 14–16pt.
6. Spell out dates consistently
Date parsing is brittle. "Jan 2023 – Present" is parsed more reliably than "1/23 – now". Use month abbreviation + full year, or full month + full year. Be consistent throughout the document.
7. Use bullet points, not paragraphs, for achievements
ATS systems and human readers both prefer bullet-pointed achievements over dense paragraphs. Bullets are easier to parse into discrete data points. Start each bullet with an action verb. Keep bullets under two lines.
8. Keep headers as plain text, not images
A surprising number of CV templates use an image of the candidate's name as the header. The name is then invisible to the ATS. Your name must appear as typed text in the document body.
9. Use DOCX, not PDF, unless specified
Discussed in depth in the next section. Short version: DOCX has a more predictable parse path on most ATS systems in production.
10. No headers and footers for critical contact info
Contact information placed in DOCX headers or footers is stored separately from the body content in the XML structure. Many parsers skip it. Put your name, email, phone, LinkedIn, and location in the main document body at the top.
Keywords: exact match vs semantic
Keyword strategy is the part of ATS optimisation that most guides get wrong. The common advice — "stuff your CV with keywords from the JD" — is both outdated and counterproductive. Here is how it actually works.
Older ATS systems use literal string matching: if the JD says "Python" and your CV says "Python", you get a point. If it says "Python scripting" and your CV says only "Python development", you may not. These systems reward exact phrasing.
Newer systems use vector embeddings to compute semantic similarity. "Machine learning" and "ML engineering" will score as near-synonyms. "Customer success" and "account management" will score as related. This makes keyword stuffing less effective and semantic coverage more important.
The practical strategy for 2026:
- Identify the three to five must-have terms in the JD — usually the role title, the primary technology or skill, and the domain (e.g., "fintech", "enterprise SaaS"). Use these exact phrases at least once each.
- For secondary skills listed in the JD, use the closest natural phrase from your real experience. If the JD says "stakeholder management" and you have done it, write "stakeholder management" — not "managing stakeholders".
- Do not repeat any keyword more than two or three times. Modern systems penalise overly repetitive text, and human readers find it off-putting.
- Do not include skills you do not have in order to pass the filter. You will be asked about them in the interview.
The best way to identify which keywords to prioritise is to compare your CV directly against the job description and see the gap. The RecastCV ATS checker does this automatically — you will see exactly which required terms are missing and where you are already covered.
For a deeper dive into extracting ATS keywords from any job description, see our guide on the ATS resume format that actually works in 2026.
.docx vs .pdf in 2026
The PDF vs DOCX debate has been running for a decade. Here is the honest answer for 2026.
Why .docx still wins for ATS submission
DOCX files store content as structured XML. A parser can walk the XML tree, identify paragraphs, headings, bullet lists, and tables, and extract their text in document order with high reliability. The structure is predictable.
PDF is a rendering format. Text in a PDF is stored as positioned glyphs on a page — not as a document structure. Extracting that text requires reconstructing reading order from visual position, which is error-prone, especially when columns, sidebars, or rotated text are involved.
Modern ATS platforms have improved PDF parsing, but legacy systems (many large enterprises still run decade-old Taleo installations) have not. Because you cannot know which system is in use, DOCX remains the safer default.
When PDF is appropriate
There are situations where PDF is preferred or required:
- The job posting explicitly requests PDF.
- You are sending your CV directly to a recruiter or hiring manager by email (not via an ATS portal) — in this case, PDF preserves your formatting precisely.
- The role is in design, media, or a creative field where visual presentation matters more than ATS compatibility.
The practical answer: keep both versions. Export your ATS-optimised CV as DOCX for portal submissions, and as PDF for direct email applications. RecastCV exports to .docx by default, which you can convert to PDF in Word or Google Docs in one click.
Test your CV
Reading about ATS optimisation is useful. Testing your actual CV against a real job description is better. The RecastCV ATS CV checker lets you upload your CV, paste a job description (or a job posting URL), and instantly see:
- Your keyword match score for that specific role
- Which required terms are present in your CV and which are missing
- ATS readability warnings (e.g., column layouts, missing contact fields)
- Suggested rewrites for low-scoring bullet points
No account required to run a check. Sign up to save results and tailor your CV directly from the checker.
If you want to go further and have RecastCV rewrite your CV to match a specific role — grounded in your real projects, not invented — see how the tailoring feature works. Or browse ATS-friendly CV templates to start from a clean, parse-safe foundation.