Horizontal scaling refers to the process of adding more machines or servers to a system to handle increased load or demand. Instead of upgrading a single server's capacity, horizontal scaling distributes the workload across multiple servers, which can improve performance and reliability. This approach is often used in cloud computing environments, where resources can be easily added or removed as needed. One of the key benefits of horizontal scaling is its ability to provide redundancy. If one server fails, others can continue to operate, minimizing downtime. This method is commonly employed by large-scale applications and services, such as those run by Amazon Web Services or Google Cloud Platform, to ensure they can accommodate fluctuating user traffic efficiently.