How the Actor Model Scales to Millions of Users

"The Actor Model allows systems to operate more efficiently by utilizing a large number of lightweight actors, freeing threads between requests, resulting in greater concurrency."

"The traditional thread-based architecture struggles with scalability, as seen in PayPal's initial reliance on 1000 virtual machines, leading to maintenance challenges and errors."

The Actor Model, implemented through Akka in Java, provides an efficient solution for building high-scale, non-blocking systems. By representing tasks as lightweight actors, each requiring threads only briefly, the system avoids bottlenecks associated with traditional thread-based models. Instead of managing thousands of virtual machines, as PayPal did, the Actor Model reduces the necessary infrastructure to a few resources, maximizing concurrency and minimizing errors. The model allows for the management of thousands of actors with a limited number of threads, significantly improving system performance and responsiveness.

Read at Medium