Is it possible to extend services through horizontal scaling without significant difficulties?

Horizontal scaling (scale-out) involves adding new instances of a service to increase overall performance and fault tolerance.

The ability to scale services horizontally without significant difficulties depends on the application's architecture:

• If the service is designed as stateless (without maintaining state between requests), scaling is usually straightforward — simply add new instances and configure a load balancer.
• If the service is stateful (with state), scaling is more complex, requiring synchronization of state or the use of external storage (e.g., databases, caches).

Other important factors include:

• Use of distributed caches and databases.
• Lack of tight coupling between components.
• Automation of deployment (e.g., through containers and orchestrators like Kubernetes).

Thus, with proper design, services can be scaled horizontally without significant difficulties, but this requires a well-thought-out architecture and infrastructure.