How to Build Your Own Projects to Learn System Design
Learn System Design by Doing: 4 DIY Projects to Level Up Your Skills
What's the best way to learn system design?
It's not by memorizing textbooks or watching endless videos.
Just like you can't learn to ride a bicycle by reading about it, you can't truly grasp system design without getting your hands dirty.
The secret?
Build something yourself.
In this blog, we'll explore how building your own projects can fast-track your system design learning, making complex concepts click through firsthand experience.
By the end, you'll know why "What I cannot create, I do not understand" – as Richard Feynman famously said – and how to start creating (and understanding) systems like a pro.
Why Learn System Design by Building Projects?
Reading definitions of load balancing, caching, or sharding is one thing; applying them in a real design is another.
This is where building your own project makes all the difference.
When you build, you turn abstract concepts into concrete decisions.
For example, it's one thing to read about database replication, but it's far more enlightening to actually implement a feature and see how your system behaves when you add a second database instance.
Here’s why project-based learning is so effective:
Active Learning: Instead of passively reading, you're actively solving problems. You encounter challenges (like scaling an app or handling errors) and learn by figuring them out.
Real Feedback: Build a simple system and try to break it. When something crashes under load or slows down, you get immediate feedback on what design component needs improvement. This hands-on trial and error sticks in your memory.
Context & Big Picture: Working on a project forces you to consider how different pieces fit together – clients, servers, databases, APIs, etc. It's like seeing the whole elephant, not just the parts. You gain a holistic understanding of system interactions.
Confidence Boost: When you’ve built (even a toy version of) a URL shortening service or a chat app, fancy terms like “distributed message queue” or “cache invalidation” become less scary. You’ve seen a bit of what they actually do in practice.
In fact, experts reiterate this approach: “The best way to master system design is by building real-world systems. Start small and progressively increase the complexity of your designs.”
Instead of drowning in theory, you learn system design by doing system design – one project at a time.
Getting Started: Basics Before Building
Before you jump into coding your grand project, make sure you understand some system design basics.
Think of this as learning the rules of a game before playing.
You should be comfortable with fundamental concepts:
Client-Server Model: Know how a basic request travels from a client (say, a web browser) to a server and back. This is the backbone of most systems.
Databases (SQL vs NoSQL): Understand that data needs to be stored somewhere, and different databases solve different needs. A social network might use a NoSQL database for flexibility, whereas a banking system might stick to SQL for transactions.
APIs: Know what an API is – essentially how different services talk to each other. When you build projects, you'll likely create simple APIs (e.g., an endpoint for shortening a URL or posting a chat message).
Scalability Basics: Be aware of concepts like horizontal scaling (adding more servers to share load) vs vertical scaling (making a server more powerful). Also understand what a load balancer does (it’s like a traffic cop distributing user requests across servers).
Caching: Recognize that caching means storing frequently used data in memory for quick access, which can drastically speed up systems.
Don’t worry if some of these are new to you.
You'll naturally learn and reinforce these concepts by building a project.
In fact, encountering them in real scenarios (even on a small scale) is one of the best ways to truly learn system design.
If any term above sounds unfamiliar, take a brief detour to read a quick overview. But don't get stuck in analysis-paralysis.
You learn by doing, so let's get to the doing!
Choose a Project Idea (Start Small)
The key to success is to start with a manageable project.
You wouldn't try to build a skyscraper as your first carpentry project; similarly, don't jump straight into designing the next Facebook or Netflix.
Pick something small enough to grasp, but meaningful enough to teach you valuable lessons.
Here are a few beginner-friendly project ideas:
URL Shortener: Design a service like "TinyURL" that converts long URLs into short links (e.g., bit.ly/xyz). This project teaches you how to handle basic client-server requests, work with a database for storing mappings, and consider issues like creating unique keys for URLs. (Bonus: think about what happens if your service gets millions of requests – you'll start considering scalability and caching.)
Library Management System: Create a simple system to manage books in a library – tracking available books, check-outs, and returns. This one is more about data modeling and consistency. You’ll design a database schema (for books, users, loans) and build a basic interface or API for operations. It’s great for learning how to design clean data models and handle concurrent updates (e.g., two people trying to check out the same book).
Chat Application: Develop a minimal real-time chat app (even if it’s just console-based or a simple web app). You’ll dive into real-time communication – perhaps using long polling or WebSocket connections. This project exposes you to designing for many simultaneous connections and messages. How will you store message history? How do you broadcast messages to the right recipients? It’s a fun way to learn about throughput and maybe even a bit of load balancing when multiple chat server instances are needed.
(Optional) Tiny “Twitter” Feed: If you want a slightly larger challenge, design a basic social media feed for a small number of users. You’ll learn about timeline generation (aggregating posts), handling read-heavy traffic (lots of people reading posts vs writing), and maybe rudimentary caching of popular posts. This can get complex, so consider it only when you’ve done one or two simpler projects first.
These projects are intentionally simplified.
The idea is not to build a planet-scale system out of the gate, but to simulate core aspects of larger systems on a smaller scale.
Starting small ensures you won’t be overwhelmed, and each project will teach you new system design concepts in context.
Once you complete a small project and feel comfortable, you can graduate to more complex ideas (for example, an online multiplayer game lobby or a ride-sharing app design) to stretch your skills further.
Interactive Tip: As you pick a project idea, pause and jot down how you would approach it.
What features should it have?
How many users do you imagine?
Even this little brainstorming is the start of system design thinking!
Design Your System: A Step-by-Step Approach
So you have a project idea in mind – great!
Now, how do you go from idea to a designed system?
It helps to follow a structured approach.
Here’s a simple step-by-step framework you can use for any system design, whether small project or big product (this framework is similar to what many experts recommend):
Clarify Requirements: Write down what your system should do. Even if it's your personal project, be specific. For a URL shortener, for instance, requirements might include: input a long URL and get a short URL, redirect users who hit the short URL to the original, maybe track how many times each short URL was used. Clearly defining the scope prevents feature creep and keeps you focused.
Define the Core Components: Identify the main pieces of your system. Typically, this includes:
Client: Who or what is interacting with your system? (Browser, mobile app, etc.)
Server/Application: The backend service that will handle logic. Will it be one server, multiple services (microservices), etc.?
Database: How and where will data be stored? (SQL database, NoSQL store, in-memory cache for quick access, etc.)
External Interfaces: Any third-party APIs or services? (For example, if building a chat, are you using a service for push notifications?)
Sketch these out. You can draw a simple diagram or even just list them. The goal is to see the big picture of the system on paper.
Design Data Models: Plan how data flows through your system and how it's structured. In our library system example, you’d decide on the tables/collections: one for Books, one for Users, one for Loans with fields for checkout date, etc. In a chat app, you consider what a Message object contains, how conversations are identified, and so forth. Good data modeling ensures your system can store and retrieve what it needs efficiently.
Consider Scalability & Reliability: This is where system design really shines. Ask yourself: What if my project suddenly had 100x more users or data? Where are the bottlenecks?
Do you need a load balancer to distribute traffic if one server isn't enough?
Should you add a cache (e.g., using Redis) to store frequently accessed data and reduce load on the database?
Do you need to partition your database (sharding) if data grows huge, or use replication for reliability?
How will you handle failures? (If a server crashes, does another take over? What happens to unsent chat messages in a crash?)
Thinking about these doesn't mean you must implement all of them for a small project. But by considering them, you learn how big systems cope with growth.
For instance, simply adding a cache to your URL shortener and measuring the speed improvement for repeated requests can teach a lot about why caching is so powerful.
This step-by-step design process is iterative.
In a real interview or large project, you might cycle through clarifying and refining requirements as new constraints come up.
For your own learning project, you have the freedom to adjust as you go – that's the beauty of being both the user and the architect!
Make sure to document your design decisions. It could be a short markdown file or even comments in your code.
Write down why you chose a certain database, or how you plan to handle increasing load.
This will reinforce your understanding and give you material to review later (or to discuss in an interview, if this project comes up).
Build a Prototype and Implement Gradually
With a clear design in hand, it's time to build the thing!
Start with a minimum viable product (MVP) – the simplest working version of your system.
If we use the URL shortener example, your MVP could be a single-server application that accepts a URL and returns a shorter URL, storing the pair in a database.
Get that working end-to-end for one user on one machine first.
Some tips for the building phase:
Pick Technologies You Know (or Want to Learn): System design is language-agnostic, so use any programming language and framework you're comfortable with. If part of your goal is to learn a new technology (say, using Node.js for the first time, or deploying on AWS), that's fine – just don't overwhelm yourself on all fronts at once.
Implement Core Use Cases First: Focus on the primary functionality before any optimizations. Make sure your chat app can send and receive messages reliably between two users before you worry about fancy features like "user is typing" indicators or message encryption. Nail the basics.
Keep It Simple: Your project is a learning tool, not a production service. Hardcoding some config values, using a simple in-memory list instead of a fully distributed queue, etc., is totally fine to start. You can always replace simple components with more scalable ones in later iterations.
Test as a User: Run your system as if you were a user. Shorten a bunch of URLs and see if they all retrieve correctly. Open two browser windows for your chat app and have a conversation with yourself to see if messages deliver. This manual testing gives insight into the user experience and might reveal bugs or design flaws early.
When your MVP works for basic scenarios, celebrate!
You've built a mini-system.
This is a huge confidence boost.
Take a moment to reflect on what was easy or hard.
Did your initial design hold up well?
Maybe your first data model needs tweaking – that's okay. Real engineers iterate on designs all the time.
Iterate: Scale Up and Add Complexity
Now comes the really fun part: make your system more robust.
Treat your project like it's gaining real traction and needs to handle more usage.
This is where you introduce more advanced system design elements one at a time, to see how they change your system’s behavior:
Add a Second Server
If your design has only one server handling everything, try simulating two servers.
How do they share data?
You might need a load balancer or to ensure both connect to the same database.
This teaches you about stateless vs. stateful design (e.g., if one server held user sessions in memory, a second server would cause issues – a hint to use a centralized session store or switch to stateless tokens).
Introduce Caching
Pick a part of your system that's a bottleneck – maybe your database is getting hit a lot for the same queries.
Integrate a simple cache (using an in-memory structure or a tool like Redis) for those frequent reads.
Measure the difference: you'll likely see your system responses get faster.
You'll also learn about cache invalidation (ensuring the cache updates when data changes) which is a classic problem in system design.
Handle More Data
Populate your system with more data or higher throughput.
For example, insert thousands of entries into your URL shortener's database and see if lookup times slow down.
This might prompt you to create an index in the database for faster search, or consider database sharding if you imagine even more data.
In a chat app, try a simple load test – send a burst of messages and observe if any get dropped or delayed.
This could lead you to implement a message queue or better concurrency control.
Simulate Failures
This is an often overlooked but valuable exercise.
Manually shut down your database while the system is running – does your app crash gracefully?
What error do users see?
Try taking one server offline – do requests seamlessly go to a second server?
These tests teach you about fault tolerance and the importance of redundancy.
Maybe you'll decide to add an active-passive database replica (one primary, one standby) or at least have clearer error handling for downtime.
At each iteration, you’re deepening your understanding of system design.
You’ll start to appreciate trade-offs: maybe adding caching improved speed but made the system more complex to maintain cache consistency.
Perhaps introducing multiple servers required you to rethink how you manage user sessions.
This is exactly what learning system design is about – understanding the impact of design decisions in a tangible way.
Remember to keep it enjoyable.
If something goes wrong, that’s a learning opportunity.
As the saying goes in engineering: failures are our friends (they show us what to fix or improve).
When your system hits a snag at higher scale, you now have a story: “Initially my chat app crashed when more than 100 people joined, so I implemented X to fix it.”
This kind of insight is gold for your learning (and makes for great discussion in interviews or tech essays, by the way).
Learn, Reflect, and Share
By now, you’ve built a project (or a few) and iteratively improved them. Take time to reflect on what you learned from each.
Ask yourself:
What concept or component gave you the most trouble, and how did you overcome it?
What would you do differently if you started over now? (This thought experiment is valuable – it means you've identified better design approaches.)
How does your design compare to real-world systems? For example, after building your URL shortener, you might read how a service like Bitly handles it and discover they use techniques you hadn’t considered. That’s okay – it broadens your knowledge.
Document your journey.
Write a short post or journal entry about your project, the design, and the issues you faced.
This consolidates your learning.
It can also serve as a portfolio piece to show potential employers or a talking point in interviews.
Imagine being asked in an interview, “Have you worked with distributed systems?”
Even if you haven’t on the job, you can confidently reply, “I built a prototype of a small-scale Twitter feed as a personal project, where I had to figure out how to handle lots of reads and writes efficiently.”
That’s impressive to many interviewers, because it shows initiative and real understanding beyond book knowledge.
Finally, consider sharing your design or discussing it with others.
You could post your design or code on GitHub, or describe your architecture on a forum (there are subreddits and communities for system design) and invite feedback.
Teaching others what you did, or just explaining it, will reinforce your knowledge and might highlight things you hadn’t thought about.
Resources to Further Boost Your System Design Skills
Building projects will give you practical experience, but it's also helpful to mix in some structured learning and see how the experts do it.
Here are a few resources and next steps to consider:
Learn from the Experts: Many large tech companies share how they design systems. Check out engineering blogs or case studies from companies like Netflix, Uber, or Twitter. For instance, Netflix has written about how they handle millions of streams, and Uber has published papers on their architecture. These can be heavy reads, but even skimming them can expose you to real-world system design decisions.
System Design Courses: If you prefer a guided path or want to ensure you cover all your bases, there are excellent courses available. DesignGurus.io offers a highly regarded series of courses: Grokking System Design Fundamentals for building a strong foundation, Grokking the System Design Interview for an interview-focused deep dive, and Grokking the Advanced System Design Interview for tackling complex, large-scale design scenarios. These courses break down system design concepts with examples and can nicely complement the hands-on practice you're getting from your own projects.
Community and Discussion: Join communities where system design is discussed. Websites like StackExchange (System Design section) or Reddit’s r/systemdesign and r/learnprogramming often have people sharing insights or asking design questions. Engaging in these can expose you to scenarios you haven't tried and prompt you to think about new problems.
Open-Source Projects & Repos: Explore repositories like the Build Your Own X compilation, which lists step-by-step guides to recreate various technologies. You don’t have to follow them verbatim, but they can spark ideas for what to build next. There's also the popular System Design Primer on GitHub, which is a free resource summarizing many concepts and includes design exercises (great to read alongside your project work).
Remember, system design is a journey, not a one-time study session.
The tech landscape evolves, and even experienced engineers keep learning new patterns and technologies.
The projects you build today to learn might even evolve into something bigger or inspire you to build the next big thing in the future!
Final Thoughts
Learning system design by building your own projects is like learning to cook by making real meals, not just reading recipes.
Yes, you’ll likely burn a dish or two (and crash a system or three), but that’s all part of the learning process.
Every mistake teaches you something that theory alone might not have.
You'll walk into interviews not only having memorized definitions, but with true stories of how you tackled designing a system, what trade-offs you considered, and what you learned from failures.
That confidence and insight will shine through.
Pick a project idea that excites you, and start building!
(Feel free to share in the comments what project you plan to build or any lessons you've learned on your system design journey.)