Cover letters and ATS software: what nobody tells you

When people talk about ATS optimization, everyone thinks of the resume. Yet in many cases, your cover letter also goes through automated filters. Applicant tracking systems, the famous ATS, analyze every document you submit, including the cover letter when one is requested.

The problem: most candidates write their ATS cover letter like a literary essay. Long sentences, a formal style, drawn-out pleasantries, but no keyword strategy whatsoever. The result: the letter doesn't strengthen the application. Sometimes it drags it down.

Understanding how ATS software handles cover letters completely changes the way you should write them.

How ATS software analyzes cover letters

Text extraction

Just as with your resume, the ATS extracts the raw text from your letter. If you send an image PDF or a file with a complex layout (columns, graphic headers, decorative text boxes), the software can miss part of the content.

So the first rule is the same as for your resume: the text must be selectable, in a simple format a machine can read.

Keyword analysis

The ATS compares the terms in your letter with those in the job posting. An ATS-friendly cover letter contains the key skills, tools, and industry vocabulary mentioned in the posting. This isn't keyword stuffing; it's a natural match between what the company is looking for and what you bring.

The letter's relative weight

In most systems, the resume carries more weight than the letter in calculating the overall score. But the letter can make the difference when two candidates have similar resumes. It can also make up for a keyword missing from your resume if that keyword appears in the letter.

In other words, the cover letter isn't the main document, but it amplifies or weakens your application. To optimize your resume at the same time, check out our comparison of the best free resume scanners.

The ideal structure for an ATS cover letter

The opening: direct and targeted

Forget classic openers like "In response to your posting on...". Your opening should immediately establish the value you bring, using terms from the posting.

Weak example: "Please accept my application for the position posted on your website."

Strong example: "As a Python developer with 4 years of experience building REST APIs and microservices architectures, I'd like to join your engineering team and contribute to your cloud migration projects."

The strong opening already contains three technical keywords taken from the posting. The ATS picks them up in the very first sentence.

The body: skills and proof

The body of the letter should map your skills to the needs in the posting. Each body paragraph should address a need identified in the job ad.

The most effective method for writing an ATS-friendly cover letter:

Identify the 3-4 main skills in the posting
Devote a short paragraph to each one, describing how you applied it in a concrete professional setting
Use the exact terms from the posting in your descriptions, not loose synonyms
Add a concrete result whenever you can: a deliverable, an improvement, a completed project

The closing: availability and a call to action

Keep the closing simple: confirm your interest, mention your availability, and invite a conversation. Avoid convoluted phrasing. A direct sentence like "I would welcome the chance to discuss how I could contribute to your team" works better than a paragraph of formal courtesies.

Formatting rules for an ATS-friendly letter

File format

Text PDF (created from Word, Google Docs, or LibreOffice): the best choice
DOCX: accepted by every ATS
Image PDF (graphic Canva export): avoid at all costs

Layout

No columns: a single column of left-aligned text
No graphic header: your contact details in plain text at the top of the document
No tables and no floating text boxes
Standard font: Arial, Calibri, Times New Roman, or any classic sans-serif font
10 to 12 point size: readable for humans, neutral for machines

Length

An ATS cover letter should be concise. Recruiters spend very little time reading each application. Three to four paragraphs, or roughly 250 to 400 words, is plenty. Every sentence should deliver useful information.

5 mistakes that sabotage your ATS cover letter

Mistake 1: No keywords from the posting

You write one generic letter and send it with every application. The ATS finds no match with the posting. The letter adds nothing to the overall score.

How to fix it: reread the posting before writing each letter. Work at least 5 to 7 technical or industry keywords into the text.

Mistake 2: A graphic format

You use a letter template with borders, sidebars, a personal logo, and icons. The ATS can't parse the content correctly.

How to fix it: use a simple text document with no visual frills.

Mistake 3: Empty sentences with no concrete content

"Dynamic and motivated, I am eager to bring my expertise to your industry-leading company." This sentence contains no usable keywords and no verifiable information.

How to fix it: replace every vague sentence with a concrete statement built on an action verb, an identifiable skill, and, if possible, a real-world context.

Mistake 4: Repeating your resume instead of complementing it

Your letter paraphrases your resume point by point. The ATS finds the same information in both documents, but you miss the chance to add extra keywords or put your skills in a different context.

How to fix it: use the letter to expand on 2-3 key experiences with a narrative angle the resume format doesn't allow. Add transferable skills or relevant projects that don't appear on your resume.

Mistake 5: Skipping the letter when it's "optional"

When a platform says the cover letter is optional, many candidates skip it. Yet submitting a well-written letter is still an advantage: it adds content the ATS can analyze and shows the human recruiter you made an extra effort.

How to fix it: always write a short letter (250 words is enough) when the option is available.

How CVpass helps you write an ATS cover letter

CVpass does more than analyze your resume. The tool identifies the priority keywords in the job posting and helps you build a complete application, resume and cover letter, that maximizes your match with automated filters.

By analyzing the posting and your background, CVpass shows you which terms to include in your letter to complement the keywords already on your resume. You end up with a consistent application where each document reinforces the other.

The result: a higher overall ATS score and an application that stands out to machines and human recruiters alike.

ATS Cover Letter: How to Write a Letter That Gets Past Automated Filters