What is Load Balancing?
Load balancing distributes incoming network traffic across multiple servers so that no single server becomes overwhelmed. It improves application performance, reliability and availability by routing each request to a healthy server and spreading the overall workload evenly across all of the available resources.
How does load balancing work?
Load balancing is the practice of distributing incoming requests across a group of servers so that no single server carries too much of the load. A component called a load balancer sits in front of the servers and acts as the entry point: it receives each request, decides which server should handle it, and forwards it on. To the user, the group of servers appears as one reliable service, even though the work is being shared behind the scenes.
The load balancer chooses a server using an algorithm - distributing requests in turn, sending each to the least busy server, or routing based on other rules such as the client's address. Crucially, it also runs continuous health checks against each server, so if one fails it stops sending traffic there and routes around the problem automatically, without any manual intervention.
Why load balancing matters
A single server has finite capacity. As traffic grows, it slows down and eventually fails, taking the whole service down with it. Load balancing solves this by spreading work across many servers, which improves performance under load, allows the service to scale simply by adding more servers behind the balancer, and removes a single point of failure from the design. It is a foundational technique for both performance and high availability, and it underpins almost every system that needs to serve large or unpredictable volumes of traffic.
What are common load balancing algorithms?
Load balancers distribute requests using strategies such as:
- Round robin - sending each request to the next server in sequence.
- Least connections - routing to the server currently handling the fewest requests.
- IP hash - mapping a client to a consistent server based on their address.
- Weighted distribution - sending more traffic to more powerful servers.
Best practices for load balancing
Always configure health checks so traffic is never sent to a failed server. Decide how to handle user sessions - either store session state externally so any server can serve any request, or use sticky sessions deliberately. Distribute across multiple availability zones for resilience, and monitor the load balancer itself, since it can become a bottleneck or single point of failure if not made redundant.
How PixelForce approaches load balancing
At PixelForce, load balancing is part of the architecture decided during Phase 1 Scoping and Design and operated through Phase 3 Post Launch Support. Our in-house Adelaide team uses it to keep products responsive and resilient - one of the techniques behind the 99.99 percent uptime our products have achieved across more than 100 builds. This work sits within our AWS app migration services capability, and it is closely tied to high availability, which load balancing helps deliver.
Where this applies
The PixelForce services where Load Balancing matters most - explore how we put it to work in client products.
Related terms
Other glossary definitions closely related to Load Balancing.
Frequently asked questions
Load balancing distributes traffic across the servers you already have, while auto-scaling changes how many servers exist based on demand. They work together: auto-scaling adds or removes servers as load rises and falls, and the load balancer then spreads traffic across whatever servers are currently running. One manages distribution, the other manages capacity, and most scalable systems use both in combination.
Yes. By spreading traffic across multiple servers and running health checks, a load balancer removes the single point of failure that one server represents. If a server becomes unhealthy, the load balancer stops routing requests to it and directs them to healthy servers instead, so users are unaffected. This makes load balancing a core technique for achieving high availability and consistent service.
Sticky sessions, also called session affinity, route a given user's requests to the same server for the duration of their session. This helps when session data is stored on individual servers. However, it can unbalance traffic and complicate failover. A common alternative is to store session state externally - in a shared cache or database - so any server can handle any request, removing the need for stickiness.
A load balancer distributes incoming requests across your servers, usually within a data centre or region, to balance work and improve reliability. A content delivery network caches and serves content from edge locations close to users worldwide to reduce latency. They solve different problems and are often used together: a CDN handles static content globally, while a load balancer manages dynamic requests across your servers.
Have an idea worth building?
Whether you are validating a concept or scaling a product, our Adelaide team can scope it properly. Book a free consultation and we will map the fastest path from idea to launch.
- Top Clutch App Development Company · Australia
- 100% in-house · Adelaide HQ
- 100+ products shipped
- 99.99% crash-free