Sharp examples of common mistakes to avoid in tech resumes

Real examples of common mistakes to avoid in tech resumes

Let’s start with actual examples of common mistakes to avoid in tech resumes that hiring managers complain about constantly. These are pulled from real-world patterns recruiters describe on LinkedIn, in HR surveys, and in tech hiring panels.

1. Bloated, buzzword-heavy summaries

Bad example of a tech resume summary:

“Results-driven software engineer with a proven track record of success. Hard-working team player with strong communication skills. Seeking a challenging position where I can leverage my skills to drive business value.”

This looks fine at a glance, but it says nothing specific. There’s no tech stack, no scale, no domains, no hint of what you actually do.

Better version:

“Backend engineer with 5+ years in Python and Go, building APIs and data services for fintech and analytics products. Designed and shipped services handling 50k+ daily active users, cut API latency by 35%, and improved deployment reliability with Docker and Kubernetes.”

When you look at examples of common mistakes to avoid in tech resumes, generic summaries are always near the top. A summary should filter you in or out quickly. If it could sit on anyone’s resume, it doesn’t belong on yours.

2. Listing responsibilities instead of impact

In 2024–2025, hiring managers are overwhelmed with candidates. They skim. If your bullets read like a job description, you blend into the noise.

Weak example:

“Responsible for developing web applications using JavaScript and React. Collaborated with cross-functional teams. Participated in code reviews.”

This tells us what you were supposed to do, not what you actually delivered.

Stronger example:

“Built and optimized React components for a customer onboarding flow, improving conversion rate from 42% to 57%. Reduced bundle size by 28% using code splitting and lazy loading, cutting time-to-interactive by 1.3 seconds.”

When people ask for examples of common mistakes to avoid in tech resumes, this is a big one: bullets that start with “Responsible for” or “Duties included” instead of a clear action + outcome.

A simple pattern that still works in 2025:

Action verb + what you did + tools/tech + measurable outcome

For example:

“Refactored legacy Node.js services into microservices with NestJS and PostgreSQL, reducing deployment rollbacks by 40% and cutting average incident resolution time from 90 to 35 minutes.”

3. Ignoring ATS and keyword reality

Applicant Tracking Systems (ATS) are not sci-fi villains, but they do screen out resumes that don’t match the language of the job description. Research from the US Equal Employment Opportunity Commission (EEOC) notes that automated tools are widely used in hiring and can affect who gets seen at all (EEOC, 2023).

Bad example:

Job description asks for:

• “AWS, Terraform, CI/CD, Kubernetes”

Your resume says:

• “Cloud technologies, infrastructure as code, modern deployment pipelines”

You technically match, but the keywords are missing. ATS may not connect the dots.

Better example:

“Implemented infrastructure as code using Terraform on AWS (ECS, RDS, S3) and set up CI/CD pipelines in GitHub Actions and Jenkins, enabling daily deployments and cutting release failures by 30%.”

When you look at examples of common mistakes to avoid in tech resumes, vague synonyms instead of the actual tech stack names are a silent killer. Use the specific tools and frameworks the role lists—if you actually have them.

4. Outdated or noisy tech stacks

Another frequent example of common mistakes to avoid in tech resumes: treating your skills section like a tech graveyard.

Messy example:

Skills: Java, C, C++, PHP, ASP.NET, jQuery, AngularJS, React, Vue, Node.js, Perl, COBOL, MySQL, Oracle, MongoDB, Redis, Docker, Kubernetes, AWS, Azure, GCP, Jenkins, Travis CI, CircleCI, Git, SVN

No one believes you actively use all of these at a professional level in 2025. It looks like copy-paste from every job you’ve ever had.

Cleaner, focused example:

Languages: Python, Go, TypeScript
Backend: FastAPI, Node.js, PostgreSQL, Redis
Cloud & DevOps: AWS (Lambda, ECS, RDS), Docker, Kubernetes, Terraform, GitHub Actions
Testing & Data: PyTest, Jest, dbt, Snowflake

Prioritize:

• Tools you’ve used in the last 3–5 years
• Skills that match the target roles
• Depth over sheer volume

If you want real examples of common mistakes to avoid in tech resumes, “I list everything I’ve ever touched” is one hiring managers complain about constantly on public forums and in surveys from organizations like the Society for Human Resource Management (SHRM.org).

5. Terrible formatting for scanning

Recruiters spend seconds, not minutes, on first pass. Eye-tracking research on resumes from career centers like MIT and Harvard shows that clear headings, consistent formatting, and scannable bullets matter for getting past that first 6–10 second skim (Harvard OCS Resume Guide).

Problematic example:

• Three-column layout
• Skills in a sidebar
• Dense paragraphs instead of bullets
• Tiny font (9 pt), minimal white space

On desktop, it’s annoying. In an ATS preview pane or on a laptop, it’s unreadable.

Better approach:

• Single column
• Clear section headings: Summary, Skills, Experience, Projects, Education
• Consistent bullet style and dates aligned on the right
• 10–12 pt font, plenty of white space

When you study examples of common mistakes to avoid in tech resumes, over-designed layouts with multiple columns and graphics are repeatedly flagged as risky. Many ATS systems flatten PDFs and misread text in sidebars or text boxes.

6. Overusing jargon and internal project names

Your future employer doesn’t know your company’s internal code names.

Confusing example:

“Led the Phoenix 2.0 migration for Project Saturn, improving TTI and TTFB for LPs by 40%.”

Unless the reader happens to have worked at your company, this is meaningless.

Clear example:

“Led migration of legacy marketing landing pages to a new React-based platform, improving Time to Interactive (TTI) and Time to First Byte (TTFB) by 40% across 120+ pages.”

One of the best examples of common mistakes to avoid in tech resumes is assuming the reader speaks your company’s internal language. Translate projects into:

• What the product or system did
• Who used it (customers, ops team, data scientists)
• What changed (faster, cheaper, more reliable, more secure)

7. No metrics, even when they exist

Not every role has obvious revenue numbers, but almost every tech job has something you can quantify: speed, reliability, volume, user behavior, cost.

Vague example:

“Improved performance of backend services.”

Specific example:

“Optimized database queries and caching strategy, reducing average API response time from 900 ms to 320 ms and cutting p95 latency by 58%.”

If you’re stuck, think in terms of:

• Speed: response time, build time, deployment time
• Scale: number of users, requests per second, data volume
• Reliability: uptime, incidents, MTTR
• Behavior: conversion rate, churn, feature adoption

Hiring managers consistently say that one of the most common mistakes to avoid in tech resumes is leaving impact implied instead of stated. If you don’t have metrics, estimate conservatively and make it clear when it’s an estimate.

8. Side projects and GitHub that don’t support your story

In 2024–2025, recruiters do click GitHub and portfolio links, especially for early-career candidates. But they’re turned off quickly by half-finished tutorials or low-effort repos.

Weak example:

• GitHub link with only forked repos and tutorial code
• Projects section listing “To-do app” and “Weather app” with no context

Stronger example:

“Personal Projects:

• Built a price-tracking Chrome extension (TypeScript, React, Firebase) with 300+ weekly active users; implemented background jobs to monitor 2,000+ product URLs.
• Trained and deployed a small LLM-based support bot (Python, FastAPI, OpenAI API) for a local nonprofit, cutting email response time from 3 days to same-day for common questions.”

When you’re thinking about examples of common mistakes to avoid in tech resumes, “I list every toy project I ever built” is high on the list. Curate. Show 2–4 projects that:

• Use modern tech relevant to your target roles
• Demonstrate end-to-end ownership
• Have a short, clear impact statement

9. Misaligned content for remote and hybrid roles

Remote and hybrid work are still common in US tech, but hiring managers are more selective. They want evidence you can communicate asynchronously and operate without hand-holding.

Missed opportunity example:

Resume lists remote roles but never mentions documentation, async tools, or cross-time-zone work.

Better example:

“Worked on a fully remote team across 4 time zones using Slack, Notion, and Jira; documented design decisions and created runbooks that reduced onboarding time for new engineers from 6 weeks to 3 weeks.”

For 2024–2025, one of the best examples of common mistakes to avoid in tech resumes is ignoring how your work style fits modern distributed teams. A single bullet that shows you can document, communicate, and collaborate remotely is worth more than another generic “team player” line.

10. Education and certifications that crowd out experience

Especially for mid-career professionals, your degree is not the main event.

Unbalanced example:

• Half a page on coursework, GPA from 10 years ago, every online course you ever took
• Two short bullets for your current role

Better balance:

• Keep education to 2–4 lines unless you’re a recent grad
• List only relevant, recognized certifications
• Move older or less relevant certs to a brief “Additional” section

For real examples of common mistakes to avoid in tech resumes, look at mid-level engineers who still lead with their college projects instead of current work. It sends the wrong signal about where your strengths are today.

How to rewrite your resume using these examples of common mistakes

Use these examples of common mistakes to avoid in tech resumes as a checklist while you edit:

• Rewrite your summary to be specific: role, years, stack, domains, impact
• Replace responsibility bullets with outcome-focused bullets
• Align your skills and keywords with 3–5 target job descriptions
• Trim outdated tech and noisy skills
• Simplify formatting to a single, scannable column
• Translate internal project names and acronyms into plain language
• Add metrics wherever you can quantify impact
• Curate projects and GitHub to tell a coherent story

A practical way to pressure-test your resume: share a draft with a friend or mentor in tech and ask them to describe, in one sentence, what you do and what you’re good at—only based on the resume. If they can’t, you still have work to do.

For more structured guidance on resume content and bias in screening tools, you can review resources from:

• The EEOC on automated hiring tools and fairness: https://www.eeoc.gov/laws/guidance/select-issues-assessing-ai-and-algorithmic-fairness
• Harvard’s Office of Career Services resume guidelines: https://ocs.fas.harvard.edu/resumes-cvs-cover-letters
• The US Department of Labor’s general job search resources: https://www.dol.gov/general/jobs

FAQ: examples of common mistakes to avoid in tech resumes

What are the most common examples of mistakes that cause instant rejection?
Real examples include unreadable formatting (tiny font, multiple columns), missing contact info, no relevant keywords for the role, and obvious copy-paste from a template with zero metrics. Another frequent example of a red flag is listing a tech stack that doesn’t match anything in your experience bullets.

Can you give an example of a weak vs strong bullet for a junior developer?
Weak: “Worked on frontend features using React."
Strong: “Implemented and tested 5+ new React components for the user profile page, fixing 12 UI bugs and improving Lighthouse accessibility score from 78 to 94.” That’s the kind of before-and-after example hiring managers remember.

Are long resumes always a mistake for tech professionals?
Not always, but for most tech roles in the US, one page is fine for early career, and two pages is plenty for mid-to-senior. When you see examples of common mistakes to avoid in tech resumes, “three-page resume with repeated bullets and old, irrelevant roles” shows up far more often than “too concise.”

Is it a mistake to include every programming language I’ve ever used?
Yes, in most cases. Better to show depth in the languages and tools you actively use now. A focused list beats a long one. If you want to show older experience, work it into your job bullets instead of padding the skills section.

What are examples of side projects that actually impress tech hiring managers?
Examples include: a tool that automates a real workflow at your current job; a small SaaS or extension with real users; an open-source contribution with merged pull requests; or a data project that answers a specific question with a clear write-up. The pattern across the best examples is the same: real users, clear purpose, and measurable impact.