- The LCU Pricing Multiplier: An AWS Application Load Balancer (ALB) charges $0.0225/hour base plus $0.008 per Load Balancer Capacity Unit (LCU-hour). However, LCUs are billed on whichever dimension peaks highest: new connections, active connections, processed bandwidth, or rule evaluations.
- WebSocket & Long-Lived Connection Penalties: High-concurrency WebSocket apps, IoT fleets, and push notification services generate hundreds of thousands of concurrent connections, triggering massive active-connection LCU bills without transmitting heavy bandwidth.
- HAProxy / Envoy Bare-Metal Parity: A single $150/month bare-metal server running HAProxy can terminate over 2,000,000 concurrent HTTP/2 connections and process 40 Gbps of line-rate traffic, replacing dozens of ALBs costing thousands monthly.
How Do AWS Load Balancer Capacity Units (LCUs) Actually Work?
The complexity of AWS ALB pricing is deliberately designed to obscure the true cost of running interactive services. Many engineers assume that if their data transfer is small, their load balancer will be cheap. However, if your API implements advanced path routing with dozens of listener rules, every single incoming request multiplies your rule evaluation dimension.
For example, if an ALB evaluates 100 routing rules per request at 5,000 requests per second, the rule dimension alone generates 500 LCUs per hour. That single routing configuration adds approximately $2,880 per month to your cloud bill for just one load balancer, compounding the billing traps documented in our cloud anomaly detection audit.
HAProxy and Envoy on Bare Metal: Line-Rate Traffic Routing
HAProxy is widely regarded in high-frequency trading and telecommunications as the gold standard for event-driven Layer 4 and Layer 7 load balancing. By leveraging Linux epoll, kernel-level zero-copy TCP splice, and CPU affinity pinning, HAProxy achieves sub-millisecond P99 latency while utilizing minuscule memory footprints.
When combined with private colocation connectivity analyzed in our bare-metal repatriation blueprint, self-hosted load balancers deliver unmetered throughput at a fraction of cloud cost.
| Metric / Billing Vector | AWS Application Load Balancer | HAProxy on Bare Metal | Forensic TCO Variance |
|---|---|---|---|
| Base Monthly Rental | $16.20 / mo per ALB instance | $180 / mo (Amortized dual-node server) | Hardware upfront vs ongoing cloud lease |
| Active Connection Fee | $0.008 per 3,000 conn-hrs | $0.00 (Unmetered RAM capacity) | 100% elimination of active conn tax |
| Data Processing Fee | $0.008 per GB processed | $0.00 (Line-rate unmetered switching) | Zero data processing surcharge |
| Monthly TCO (300k conns, 50 TB) | $6,140 / month | $380 / month (Colo power + network) | 93.8% net monthly operating savings |
When Does AWS ALB Still Justify Its Pricing?
For external-facing, high-volume production applications, continuing to rely on ALB without investigating bare-metal or self-hosted ingress alternatives is leaving thousands of dollars in margin on the table every month. Review our high-cardinality telemetry benchmarks for complete guidance on monitoring self-hosted network components.
People Also Ask
What is the difference between an ALB and an NLB in AWS?
An Application Load Balancer (ALB) operates at Layer 7 and inspects HTTP/HTTPS headers, cookies, and paths. A Network Load Balancer (NLB) operates at Layer 4, forwarding raw TCP/UDP packets with ultra-low latency, but bills via Network Load Balancer Capacity Units (NLCUs).
Can HAProxy handle automated Let’s Encrypt SSL certificates?
Yes. Using Certbot or the native HAProxy ACME Lua plugin, HAProxy provisions and auto-renews free Let’s Encrypt TLS certificates without manual administrator intervention.
How does HAProxy achieve high availability across servers?
HAProxy clusters achieve high availability using Keepalived and VRRP (Virtual Router Redundancy Protocol) to share a floating Virtual IP (VIP), or via BGP Anycast routing across multiple physical rack switches.
Related AWS Networking FinOps Audit:
To identify and eliminate additional proxy and load balancing surcharges across your AWS VPC, see our teardown on Replace AWS NAT Gateway: fck-nat vs. $0.045/GB Cloud Tolls.
Related High-Throughput Ingress & Load Balancing:
To evaluate load balancing architectures and eliminate AWS LCU surcharges, review our benchmark on AWS API Gateway Costs: Kong on Bare Metal FinOps Guide.