Most developers spend their time building APIs, dashboards, and CRUD systems.
But at some point, I wanted to go deeper — to understand how servers actually work at a lower level.
So I built a simple non-blocking multithreaded TCP server in C++.
Why this project?
This wasn’t about building something production-ready.
It was about learning:
- How TCP servers handle multiple clients
- What “non-blocking I/O” really means in practice
- How multithreading impacts performance and scalability
- The hidden complexity behind backend systems
Core Concepts
1. TCP Sockets
The foundation of communication between client and server.
Using low-level socket APIs gives full control — and full responsibility.
2. Non-Blocking I/O
Instead of waiting for operations to complete, the server continues execution.
This avoids:
- Blocking the entire process
- Wasting CPU cycles on idle connections
3. Multithreading
Each connection can be handled independently, allowing multiple clients to interact with the server simultaneously.
But this introduces new challenges:
- Thread management
- Synchronization issues
- Resource contention
Key Challenges
While building this, I ran into several real-world problems:
- Creating too many threads can kill performance
- Poor synchronization leads to race conditions
- Mixing non-blocking I/O with threads requires careful design
This is where you start understanding why modern systems use:
- Thread pools
- Event loops (like epoll)
- Hybrid architectures
What I Learned
This project changed how I see backend systems.
Things that look “simple” at a high level — like handling requests — are actually complex under the hood.
You start to appreciate:
- Node.js event loop
- Nginx architecture
- High-performance networking systems
What’s Next?
I’m planning to evolve this project into something more advanced:
- Replace thread-per-connection with a thread pool
- Introduce event-driven I/O (epoll)
- Build a custom protocol on top of it
- Benchmark performance under load
Source Code
Check out the project here:
https://github.com/HenriquesOmbisa/mojo-raw-cpp
Final Thoughts
If you’re a developer and you’ve never built something like this, I highly recommend it.
It forces you to think differently.
It pushes you beyond frameworks.
And it gives you a real understanding of how systems work.
This is where software engineering actually begins.
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