Beginner's System Design Guide: Building High-Performance Web Apps
Imagine you are building a simple web application based on your idea. After weeks of development, testing, and debugging, you finally launch it. Everything works smoothly, and about 100 users start using your application daily.
The server handles the requests easily, the database performs well, and the application feels fast and reliable.
Then one day, your application suddenly gains traction, and 1,000 users start using it. What seemed like a success quickly turns into a problem. The server begins to crash, requests start timing out, and the database struggles to handle the increased load.
At this point, writing clean and efficient code is no longer enough. To support growing traffic and maintain performance, you need something more fundamental: good system design.
What is System Design?
System design is the process of defining the architecture, components, modules, interfaces, and data flow of a system so that it can handle scale, reliability and performance requirements.
Instead of focusing on a single function or class, system design focuses on how the entire system works together.
Who should learn System Design?
System design is essential skill for every software engineer who is involved in building or maintaining software systems that need to scale, remain reliable and perform efficiently.
While it is often associated with senior engineers, software engineers at every stage of experience should understand some part of the methods of scaling their applications.
Although system design is often associated with senior engineers, software engineers at every stage of their careers should understand the fundamental principles of designing and scaling applications.
Before going in depth in system design, in this article, we are going to understand few terminologies that we are going to use in next articles.
Client
Client is any device or application that sends a request to a server to access the service.
Generally, it is the GUI application like web application or mobile application which we use to access the application.
Server
A server is a machine or program that receives requests from clients and responds with data or services.
In many system design discussions, the term server is often used interchangeably with machine.
In this series, we may sometimes refer to a server as a machine, and both terms should be considered to mean the same thing unless stated otherwise.
IP Address
An IP address is a unique identified assigned to every device connected to a network.
Computers use IP address to communicate with each other across the internet. Example: 192.168.1.1
Domain Name System (DNS)
In simple terms, the Domain Name System (DNS) acts like a phone book for the internet.
Every application or website on the internet is associated with an IP address. Computers use these IP addresses to identify and communicate with each other, but it is difficult for humans to remember them.
Humans prefer to remember meaningful and easy-to-read names instead of numerical addresses.
DNS translates human-friendly domain names such as google.com or facebook.com into computer-readable IP addresses like 192.0.0.1.
HTTP/HTTPS
HTTP is the short form of Hypertext Transfer Protocol.
It is a protocol used for communication between clients and servers on the web.
HTTPS is a secure version that encrypts the data during transmission.
Load Balancer
A load balancer distributes incoming traffic across multiple servers.
Large platforms like Google, Facebook use load balancing to serve millions of users. It helps in preventing server overload, improving reliability and ensuring high availability.
Database
A database is an organised collection of data that is stored and managed using a Database Management System (DBMS).
Databases are generally categorised into two main types: SQL and NoSQL. In future articles, we will explore both of these database types in more detail.
Cache
A cache is a temporary storage used to store frequently accessed data so it can be retrieved faster.
With proper use of caching, the load on the database can be significantly reduced, which improves the overall performance of the application.
API
API is the short form of Application Programming Interface. An API allows different software systems to communicate with each other.
For example, a mobile app communicates with backend server via API.
Latency
Latency refers to the time it takes for a request to travel from the client to the server and back.
Lower latency means faster response time of the application.
In the next article, we will dive deeper into one of the fundamental concepts of distributed systems: the CAP Theorem, and understand how it influences the design of modern scalable systems.