Introduction: Why Pet Projects Matter
A few years ago, while searching for an apartment with my future wife, I got frustrated with fake rental listings. Scammers would copy photos from legitimate ads and repost them as bait for unsuspecting renters. That frustration led me to build an image search system that could detect when the same photos appeared across multiple advertisements.
I didn’t treat this side project seriously at first—it was just a weekend experiment to solve my own problem. But it ended up changing my perspective on career development, and became my strongest asset in job interviews.
I’m sharing this story because I think many engineers underestimate what pet projects can do for their careers. If my experience can convince even a few developers to start their own side projects, this article will have served its purpose.
Growth Beyond the Day Job
Pet projects develop technical skills differently than everyday work. They offer chances to experiment with new frameworks, languages, and tools that don’t fit into regular assignments. More importantly, they force engineers to think about products as a whole.
In most companies, backend, frontend, and product teams operate independently. Each team optimizes its own domain but rarely sees how the pieces connect. A pet project changes that dynamic. You take full responsibility, from defining the user problem to deploying the solution, which helps you understand how systems interact in production and builds respect for other roles.
Want to try that new React framework everyone’s discussing? Or experiment with Rust for performance-critical code? Pet projects give you this freedom. At work, you’re constrained by team standards, legacy systems, and “if it ain’t broke, don’t fix it” mentality.
Experimentation Without Risk
Every new framework or paradigm you try for the first will always turn out terrible. That’s just how it works when you’re doing something for the first time.
This reality makes production experimentation risky. Corporate teams focus on stability and delivery schedules, leaving little room for trial and error. When you’re responsible for high-traffic systems, your main goal is to keep them running.
But when corporate development is outsourced to agencies, the opposite often happens. I’ve seen this firsthand in agency work: developers eager to try new tools use client projects as test beds. The result is predictable: technical debt, missed deadlines, and solutions that don’t fit the problem. Production systems end up carrying the cost of experimentation.
Pet projects fill this role better. It’s safe to try a new database, test an unfamiliar framework, or build deployment pipelines with experimental tools. If something fails, the cost is only time spent, and the lessons transfer to professional work later.
Pet projects give you safe space to experiment with:
- New databases like MongoDB or PostgreSQL when you’re stuck with MySQL at work
- Modern frameworks like Next.js or SvelteKit without risking production stability
- DevOps tools like Docker or Kubernetes before your company adopts them
- Alternative architectures like microservices or event-driven design
Early failures in personal projects prevent bigger failures at work, while keeping production systems clean and giving engineers space to learn through trial and error.
Value for Employers and Business
Employers notice when candidates maintain side projects. In healthy companies, this is seen as a positive signal of curiosity and initiative beyond a skills checklist. In some places, however, side projects may be restricted, so it’s worth checking your company’s policy. In interviews, pet projects become stories about real challenges and actual solutions, demonstrating independence and creativity in action.
Recently I had an interview at a tech company. They started with standard coding challenges. Then came the crucial question: “Tell us about your most interesting project.” I spent an hour walking them through my image search system, explaining the technical architecture, the unexpected pivot in user base, and the lessons learned. Their reaction was immediate: “That’s really impressive.”
That project became my strongest interview asset because I could discuss every decision without confidentiality restrictions. I could show working code, explain the reasoning behind architectural choices, and demonstrate problem-solving skills through a complete project lifecycle.
For hiring managers, these projects prove that engineers stay motivated to keep learning. Instead of only describing known tools, you can walk through situations where you identified problems, designed solutions, and pushed them to working states. These stories reveal more about capabilities than buzzword-filled résumés.
Companies also prefer when experimentation happens outside production and gets brought back responsibly. Pet projects complement professional work by showing growth without hurting business priorities, making them positive signals in hiring decisions.
Case Study: Image-Based Fake Rental Detection
My rental fraud detection project illustrates these lessons clearly. The technical challenges were substantial since I needed algorithms for image comparison that could handle cropped photos, resized images, and added watermarks. Linear search was too slow for millions of images, so I implemented distributed search using prefix trees and achieved sub-second search times.
The image processing pipeline involved extracting key points using AKAZE algorithms, generating binary descriptors, and storing them in memory-optimized data structures. I had to balance accuracy with performance—too strict matching missed valid duplicates, while loose matching produced false positives. Finding the right Hamming distance threshold required testing against thousands of known image pairs.
The system processed 150,000 images daily across multiple servers and required careful attention to memory management and distributed architecture. These were problems I’d never encountered in typical backend development work. Even with a simple prototype, the project gave me hands-on experience with computer vision algorithms, distributed systems design, and performance optimization at scale.
The product side proved equally educational. I assumed apartment hunters would use the tool to avoid scams. In practice, real estate agents became the paying customers. They wanted to validate their own advertisements and research competitors. A project that started as protection against real estate agents became a product they actually paid for.
This pivot taught me how different actual users can be from initial assumptions. It demonstrated both the technical depth and product lessons that a single pet project can deliver. The experience became a compelling interview story that showcased technical problem-solving, architectural thinking, and product intuition—skills difficult to demonstrate through typical corporate work examples.
Staying Current in a Dynamic Industry
Technology moves fast, but companies often don’t. You might be stuck maintaining jQuery while the industry has moved to React, or working with monoliths while everyone talks about microservices. Pet projects act as personal research labs that close this gap.
Experimenting with GraphQL in a side project makes it much easier to advocate for adoption when your company considers API improvements. Trying serverless platforms at home reduces the learning curve when your team finally makes that shift. This habit builds resilience—instead of fearing change, you already have practical experience with new solutions.
Conclusion
Pet projects deserve more than a few hours of weekend coding. My rental fraud detector started as a simple frustration but became one of my most valuable career assets. Your project doesn’t need to be groundbreaking—it just needs to be yours.
Getting started is simple:
- Pick a problem you actually face in daily life
- Choose one new technology to experiment with
- Start small—build something you can finish in weekends
- Document your decisions and lessons learned
Find a problem that genuinely interests you. Build something small but complete. Learn from what goes wrong along the way. In a field where technology changes quickly, personal projects help you stay current without waiting for corporate approval to try new tools.