I've Helped 50+ Engineers Rewrite Their Resumes. The Same 3 Mistakes Appear Every Time.

Source: Dev.to

Over the past year, I’ve reviewed resumes for friends, colleagues, boot‑camp grads, and strangers on Reddit. After 50+ reviews, I can spot the three mistakes within 10 seconds. Every single resume has at least one.

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Mistake 1: Describing Responsibilities Instead of Achievements

This is in ~90 % of resumes

❌ "Responsible for developing and maintaining the company's 
    web application using React and Node.js"

This tells me you had a job. It doesn’t tell me you were good at it.

✅ "Rebuilt the checkout flow in React, reducing cart 
    abandonment by 23 % and increasing monthly revenue 
    by $45 K across 200 K monthly active users"

The formula:

[What you did] + [How you did it] + [What changed because of it]

The what changed part is everything. It’s the difference between “I was present” and “I made an impact.”

“But I Don’t Have Exact Numbers”

Estimate responsibly.

Hiring managers don’t have lie detectors; they have a credibility & impact detector. Specific (but honest) numbers pass that filter. Vague descriptions don’t.

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Mistake 2: The Undifferentiated Skills List

❌ Skills: JavaScript, React, Node.js, Python, Java, C++, 
   HTML, CSS, SQL, MongoDB, AWS, Docker, Git, Agile, 
   teamwork, communication, problem‑solving, Microsoft Office

This list is 23 items long and tells me nothing. Every developer lists the same technologies. Adding “teamwork” and “Microsoft Office” actively hurts you.

✅ Languages: TypeScript, Python, Go  
   Front‑end: React, Next.js, Tailwind CSS  
   Back‑end: Node.js, FastAPI, PostgreSQL  
   Infrastructure: AWS (ECS, Lambda, RDS), Docker, Terraform  
   Observability: Datadog, Sentry, PagerDuty

Rules

1. Categorize. Grouped skills are parsed correctly by ATS and read faster by humans.
2. Remove soft skills. “Teamwork” belongs in your experience bullets, not your skills list. Show it, don’t list it.
3. Remove obvious stuff. “Git” and “HTML” are assumed for any developer. Listing them wastes space.
4. Be specific about cloud. Not just “AWS” – “AWS (ECS, Lambda, RDS, S3).” This matches specific job requirements.
5. Match the job posting. If they ask for “Kubernetes,” your resume should say “Kubernetes,” not “container orchestration.”

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Mistake 3: One Resume for Every Application

I reviewed a candidate who sent 120 applications with zero responses. The resume was fine for a generic “software engineer” role, but they were applying to frontend, backend, data‑engineering, and DevOps positions with the same document.

Each posting has specific keywords that ATS matches against your resume. A frontend posting wants “React, TypeScript, responsive design, accessibility.” A backend posting wants “API design, PostgreSQL, microservices, Docker.” If your resume mentions all of these equally, it matches none of them strongly.

The System

1. Create a master resume with all your experience, every bullet, every skill. This is your source of truth. It can be 3 pages—nobody sees it.
2. For each application, create a tailored copy:
   • Reorder skills to match the posting’s priorities.
   • Swap 2‑3 experience bullets to highlight relevant work.
   • Adjust the summary to mirror the employer’s language.

Time investment: ~8 minutes per application. Yes, you’ll send fewer applications—but 10 tailored applications get more interviews than 100 generic ones.

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Bonus Mistake: Formatting That Breaks ATS

This isn’t one of the “big three” because most people have heard about ATS‑friendly formatting, yet I still see:

The test: Copy your resume, paste it into Notepad (plain text). Does the structure survive? Can you read it? If yes, ATS can read it. If it’s garbled, reformat.

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The Before/After That Changed My Mind

Before

Software Developer at TechCorp (2022‑Present)
- Developed web applications
- Worked on team projects
- Improved code quality
- Participated in code reviews

After (same person, same job)

Software Engineer | TechCorp — Fintech SaaS, 500 K users 2022–Present

• Rebuilt payment‑processing pipeline in TypeScript, reducing failed transactions by 34 % (from 2.1 % to 1.4 %) and recovering ~$180 K in annual revenue  
• Designed and shipped a real‑time fraud‑detection system using Kafka and Redis, flagging suspicious transactions in <200 ms with 96 % accuracy  
• Reduced deployment time from 45 min to 8 min by migrating CI/CD from Jenkins to GitHub Actions with parallel test execution  
• Mentored 2 junior developers through their first 6 months; both now contribute independently to the payment team

Same person. Same job. Same experience. One version gets filtered by ATS. The other lands interviews. The difference is ~30 minutes of rewriting.

💡 I put together a Tech Resume Toolkit to help you apply these fixes quickly.

Cleaned Markdown

[Tech Resume Toolkit](https://ve.gumroad.com/l/tech-resume-toolkit) includes:

- 3 ATS‑tested templates (Junior, Senior, Career Switcher)  
- An action‑verb bank  
- A step‑by‑step rewrite guide  

Everything in this article, packaged so you can apply it in **30 minutes**.

*Want me to look at your resume? Drop a comment or DM me — I do quick reviews when I have time.*