I've Reviewed 200+ Developer Portfolios. 90% Make the Same 4 Mistakes.

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I've Reviewed 200+ Developer Portfolios. 90% Make the Same 4 Mistakes.Matthew Hou

I've been doing informal portfolio reviews for junior and mid-level developers for the past two...

I've been doing informal portfolio reviews for junior and mid-level developers — usually someone from a Slack community or Reddit asking for feedback before applying somewhere.

After reviewing 200+, the patterns are relentless. The same four mistakes show up over and over. And the frustrating thing is that none of them are hard to fix.

Mistake #1: Leading with Technology, Not Outcomes

What I see:

"Built a full-stack e-commerce app using React, Node.js, PostgreSQL, Redis, and Docker. Implemented JWT authentication, role-based access control, and real-time inventory updates."

What a hiring manager reads: "Used a bunch of technologies to build... something."

The most common mistake is writing project descriptions for engineers, not for the people evaluating you. You've correctly listed every technology you touched. You haven't told me what the project actually does, who it's for, or whether it worked.

What to do instead:

Lead with the outcome, then explain how you achieved it.

"Built a product that lets small e-commerce stores track inventory in real time, preventing overselling during peak traffic. Handles concurrent inventory updates using optimistic locking in PostgreSQL with Redis as a cache layer — the system maintained accuracy across 200 simultaneous test users without a single oversell."

Same project. Same technologies. But now I understand what you built and I have a signal about whether it actually works.

The framework: Who uses it? What problem does it solve? What's a concrete result or scale you achieved?

Mistake #2: Showing Projects You Can't Talk About

This one gets people in interviews.

A portfolio full of projects built in a 3-day sprint to impress reviewers is a liability, not an asset. When I ask "walk me through a technical decision you made on this project," the answer reveals whether you actually understand what you built.

The tells:

  • "I just followed a tutorial"
  • "I'm not sure why I used [library], I saw it recommended somewhere"
  • Changing a database from MySQL to PostgreSQL for no architectural reason (tutorial drift)

What to do instead:

Pick 2-3 projects you can talk about for 20 minutes each. Know:

  • Why you chose the architecture you did (and what you'd do differently)
  • What the hardest technical problem was and how you solved it
  • What you would change if you rebuilt it today
  • What you learned

Depth beats breadth. Three projects you understand completely beat ten projects you barely remember building.

Mistake #3: No Signal That It Works

I cannot count the number of portfolios where I clicked "Live Demo" and got a Heroku error page. Or a blank screen. Or a login form with no test credentials listed.

This sends a specific message: the developer doesn't test things from the user's perspective. That's a red flag for a role where you'll be responsible for things working.

What to do instead:

If your project is deployed:

  • Test the link every time you update your portfolio
  • If the free tier spins down (Render, Railway, etc.), add a note: "Demo may take 30 seconds to wake up"
  • For projects that require auth, add a clearly labeled test account

If your project isn't deployed and you don't want to pay for hosting:

  • Video demos work. A 2-minute screen recording of the key features is better than a broken live link.
  • GitHub with a clear README that explains how to run it locally is fine.

The bar isn't "perfect." The bar is "clearly functional."

Mistake #4: The "About Me" Section is a Resume Reprint

The about section should make me want to talk to you. Instead, most of them read like a LinkedIn profile bullet-point dump.

What I typically see:

"I'm a full-stack developer with 2 years of experience. I have expertise in React, Node.js, and Python. I'm passionate about building user-friendly applications and always eager to learn new technologies."

This tells me nothing. Every portfolio says this. "Passionate," "eager to learn," and "user-friendly applications" are filler.

What works:

Tell me something real.

  • What kind of problems do you actually find interesting? Distributed systems? UX challenges? Performance optimization?
  • What's something you built or fixed that you're genuinely proud of? Even if it's small.
  • What's your development philosophy? What do you care about?

A real example (condensed):

"I tend to obsess about the user experience of developer tools — CLIs, APIs, documentation. I think most developer tooling is terrible and I've spent more time than I'd like to admit trying to fix the tools I use at work. I built a custom wrapper around our deployment scripts that reduced a 23-step process to 4 commands, and watching other engineers actually use it every day is more satisfying than any feature I've shipped."

That person has an opinion. They care about something specific. That's a portfolio I'll remember.

The Portfolio That Gets Interviews

After 200+ reviews, the portfolios that consistently lead to interviews share these qualities:

  1. Fast load, simple design. The portfolio's job is to get out of the way. It shouldn't take longer to load than it does to read.

  2. 3-4 projects with depth. Not 10 shallow ones.

  3. Evidence the stuff works. Live demo, video, or clear instructions.

  4. An "about" that sounds like a human wrote it. With opinions.

  5. Easy to contact. One clear CTA. Email, LinkedIn, GitHub — pick the one you'll actually respond to.

That's it. Not revolutionary. But 90% of portfolios I've seen fail at least two of these.

Fix the basics before worrying about the design.

What's been the hardest part of your portfolio to get right? I'm curious if there are patterns I'm missing.