Granular control over routing decisions
Load Balancer
Our Layer 7 Load Balancer lets you define content-aware routing decisions while ensuring instant convergence and failover. Unlike DNS-based solutions, our Load Balancer gives you granular control, immediate scalability, and real-time visibility.
Content-aware load balancing for any infrastructure
Content-aware routing
We balance HTTP and HTTPS requests to your servers using granular content-aware routing decisions and allow you to create custom rules to route traffic using various request aspects. This lets you better support your application architecture and optimize client responses before delivery.
Highly configurable
Our dynamic server functionality allows you to programmatically add, delete, or modify your servers. Instant convergence means you won’t have to wait for time-to-live (TTL) changes on DNS records, and automatic HTTP-based health checks confirm that requests go to healthy and responsive servers.
Flexible and scalable
Use us as a global server load balancer (GSLB) or local server load balancer (LSLB) within each data center or cloud region. Our load balancer can also instantly scale to multiple terabits per second (Tbps) for cost efficiency and transparency.
Features
Fastly Load Balancer
Our load balancer is built on top of the Fastly edge cloud platform, so you also get the benefits of granular control, immediate scalability, and real-time visibility. You can easily add other Fastly services to provide a unified architecture across your entire application, including core delivery, DDoS, and WAF.
Infrastructure-agnostic distribution
You can use Fastly as a global server load balancer (GSLB) to route traffic across any geographically distributed infrastructure deployments. We also act as a local server load balancer (LSLB) within each data center or cloud region.
Immediate control
Our dynamic server functionality allows you to programmatically add, delete, or modify your servers without having to version your VCL. You can also add, delete, or modify your custom routing rules via API.
Traffic scalability
Fastly’s architecture enables our load balancer to instantly scale to multiple terabits per second (Tbps) for cost-effectiveness and transparency.
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Frequently Asked Questions
What is a load balancer?
A load balancer distributes incoming traffic across multiple backend servers to optimize performance, availability, and reliability. By intelligently routing requests, load balancers prevent any single server from becoming overloaded and help ensure consistent application delivery at scale.
How does server load balancing improve application performance?
Server load balancing improves performance by:
- Distributing traffic across healthy origins
- Reducing latency through intelligent request routing
- Preventing bottlenecks during traffic spikes
- Increasing fault tolerance and uptime
Fastly performs load balancing at the edge, allowing traffic decisions to be made closer to users, before requests reach origin infrastructure.
What is a global load balancer?
A global load balancer routes traffic across geographically distributed data centers or regions. It uses health checks, latency signals, and availability data to direct users to the optimal origin, improving resilience and performance for globally distributed applications.
Fastly’s global load balancing runs on its edge network, enabling real-time, worldwide traffic steering without centralized bottlenecks.
What is a Layer 7 load balancer?
A Layer 7 load balancer operates at the application layer (HTTP/HTTPS) and makes routing decisions based on request attributes such as:
- URLs and paths
- Headers and cookies
- HTTP methods
- Application logic
Layer 7 load balancing provides finer control than Layer 4 approaches and is ideal for modern, API-driven and microservices-based architectures.
How does Layer 7 load balancing work at the edge?
With Layer 7 load balancing at the edge, Fastly evaluates requests in real time as they enter the network. Traffic can be routed dynamically based on application context, backend health, or custom logic—without adding latency or requiring origin changes.
How does Fastly’s load balancing differ from traditional load balancers?
Traditional load balancers are often centralized or region-bound, which can introduce latency and single points of failure. Fastly’s load balancing is:
- Edge-native and globally distributed
- Fully programmable via VCL and APIs
- Integrated with real-time health checks
- Designed for instant traffic failover
This enables faster, more resilient server load balancing at internet scale.
Can Fastly route traffic based on backend health?
Yes. Fastly continuously monitors backend health and automatically routes traffic away from unhealthy origins. This ensures high availability and minimizes user impact during outages or degraded performance.
Does Fastly support multi-cloud and hybrid architectures?
Absolutely. Fastly’s global load balancer can distribute traffic across:
- Multiple cloud providers
- On-premise data centers
- Hybrid and multi-region environments
This flexibility helps organizations avoid vendor lock-in and design for resilience.
How does load balancing integrate with Fastly’s edge platform?
Fastly load balancing integrates seamlessly with:
- Fastly CDN
- Edge Compute
- Web Application Firewall (WAF)
- DDoS Protection
Together, these capabilities allow teams to control, secure, and optimize traffic flows from the edge to the origin.
Is Fastly load balancing suitable for high-traffic applications?
Yes. Fastly’s load balancing is built for high-volume, latency-sensitive workloads, making it well suited for:
- Media and streaming platforms
- SaaS and API-driven applications
- E-commerce and global digital services
Its edge-based architecture enables predictable performance even during sudden traffic spikes.
How quickly can teams deploy Fastly load balancing?
Fastly load balancing can be deployed quickly using configuration-based setup and APIs, with no application code changes required. Teams can begin managing traffic distribution and failover within minutes, while maintaining full control over routing logic.