What are the key considerations to keep in mind when designing a system that needs to scale horizontally?

During my final year in college, I worked on a group project to develop a web application for student collaboration. We knew the app might need to handle many users, so we designed it with horizontal scaling in mind. We used a microservices architecture, where each service handled a specific function like authentication, messaging, and file storage. This allowed us to add more instances of each service as needed. We also implemented a load balancer to distribute user requests evenly across the servers. This project taught me the importance of designing systems that can grow with user demand, which is essential for any application in a real-world scenario.

I volunteered to help organize a community event, which required managing registrations and participant communications. To ensure everything ran smoothly, I created a simple online registration system. I anticipated a high number of attendees, so I set up the backend to allow multiple volunteers to handle incoming registrations simultaneously. By using a shared spreadsheet for data entry, we could easily scale our efforts. This experience showed me the value of planning for potential growth, even in small projects, and how effective teamwork can help manage increased demands.

In my first job, I joined a team responsible for an e-commerce platform that experienced heavy traffic during sale events. I was involved in discussions about horizontal scaling strategies. We focused on making our application stateless, so any server could handle any request, making it easier to add more servers as needed. We also explored database sharding to manage large volumes of data across multiple servers. This experience highlighted the critical nature of planning for scalability early in the development process to ensure a seamless experience for users.