A caveat first
An applicant tracking system (ATS) is the software many employers use to collect and search applications. There are many ATS products, they change often, and vendors do not publish in detail how their parsers work. So nothing here claims that a specific system scores, ranks or rejects resumes in a particular way. What follows is commonly recommended practice that makes a resume easier for software, and for the person reading it, to handle.
What a keyword gap is
Recruiters commonly search candidate databases for skills, tools and certifications. If the posting says "Kubernetes" and your resume says "container orchestration", you may have the skill and still not come up in a search for that word.
A keyword gap is any skill, tool or qualification that meets three conditions: the posting names it, it is true for you, and your resume does not state it in the posting's words. The middle condition matters most. A term you could not back up in an interview is not a gap. It is something you do not have, and it stays off the page.
Step 1: pull the terms out of the posting
Put the posting and your resume side by side. Go through the posting and write down every hard skill, tool, platform, language, method and certification it names. Skip the adjectives ("fast-paced", "collaborative") and keep the nouns. Note which terms sit under the requirements and which under "nice to have", because the first group deserves your attention first.
Step 2: sort each term into three groups
- Already on your resume, in the posting's words. Nothing to do.
- True for you, but missing or worded differently. This is the gap. Typical causes are an in-house tool name instead of the industry one, an acronym without the full name (or the reverse), and a skill you used every day and never thought to write down.
- Not true for you. Leave it out.
Step 3: close the gap inside an experience bullet
For each term in the second group, use the posting's exact wording at least once. The best place is an experience bullet that shows how you used it, not only a skills list. Compare:
- Before: "Maintained deployment tooling for the platform team."
- After: "Maintained Terraform modules and GitHub Actions pipelines that the platform team used to deploy services to AWS."
The second version names three searchable terms, each attached to something you did. It only works if it is accurate: this is an illustration, and your own bullet has to describe your own work.
Do not paste a block of terms at the bottom of the page or repeat one word in every bullet. Once or twice, in context, is enough. A person will read this page too.
Step 4: check that the words can be read
The right terms do not help if they sit in a part of the file that software handles badly. Three quick checks:
Run the plain-text test. Open the file, select all, copy, and paste into Notepad, or into TextEdit in plain-text mode. Read it from top to bottom. This shows roughly what a parser has to work with. If text is missing, out of order or scrambled, fix the layout and test again.
Move key information out of columns, tables and text boxes. Multi-column layouts and text boxes are commonly reported to come out of parsers in the wrong order, or not at all. Use a single column and move sidebar content, such as your skills, into a normal section.
Use standard section headings. Summary, Experience, Education, Skills, Certifications and Projects are labels a stranger expects. A heading like "Toolbox" or "My Journey" may not be recognized as a section, and your new keywords are sitting under it.
Then save the file as .docx or a text-based PDF, unless the posting asks for something else. Use "Save as PDF" or "Export" rather than a print-to-image option.
Step 5: repeat for each posting
You do not need a new resume for every application. Keep one complete master version. For each posting, repeat steps 1 to 3: list the terms, find the few that are true for you and missing, and work them into bullets you already have. Give each version a clear file name so you know which one went where.
If most of a posting's required terms land in your "not true for me" group, that is useful information too: it may be a posting to skip, or a skill to learn next.
Going further
The keyword check is one of 20 checks in the ATS checklist included in the Tech Layoff Job-Search Kit, our own paid product, sold on Gumroad as 4 Markdown files. The kit page describes each file, the delivery method and the refund policy.