Horizontal scaling

Horizontal scaling

When the API becomes the basis of a product and begins to process tens of thousands of requests per second, it is critical to ensure horizontal scaling. This means adding new instances without stopping the service and distributing the load between them using balancers.

We design and implement a scalable API architecture that can grow flexibly and withstand any peak load.

How horizontal scaling works

Component	What Does
Load balancer	Distributes incoming traffic between API servers (HAProxy, Nginx, AWS ELB)
API instances	Independent copies of API applications processing requests in parallel
Shared Data Store	Centralized Database or Cache Accessible to All Instances
Health-check and auto-recovery	Instance availability control and automatic recovery

Why do you need it

Robustness in case of sharp growth of requests
Fault tolerance - failure of one node does not affect API operation
Support for wide scaling without changing application logic
Ability to roll out updates in stages (rolling update)
Cost optimization through dynamic scaling

What we use

Load balancers: HAProxy, Nginx, AWS ELB, GCP Load Balancer
Orchestrators: Docker Swarm, Kubernetes, ECS
Кеш и shared state: Redis, Memcached, S3
Monitoring: Prometheus, Grafana, Datadog
CI/CD: Automatic dumping of new instances by load

Where critical

Financial and banking APIs
Realtime games and streaming services
E-commerce during sales and peak loads
Products with global coverage and GEO distribution

Horizontal scaling is the architectural foundation for growth. We will ensure that your API will work on any volume of traffic, with high fault tolerance, dynamic scaling and constant availability.