ALB vs NLB vs GWLB.

In Simple Words:

• ALB (Application Load Balancer): Layer 7 (HTTP/HTTPS/gRPC). Path-based routing, host-based routing, SSL termination, and WebSockets.
• NLB (Network Load Balancer): Layer 4 (TCP/UDP/TLS). Ultra-high throughput, millions of requests/sec with ultra-low latency, and provides static Elastic IPs.
• GWLB (Gateway Load Balancer): Deploys and scales third-party virtual network appliances (firewalls, deep packet inspection).

# Application Load Balancer path-based listener rule:
resource "aws_lb_listener_rule" "api_routing" {
  listener_arn = aws_lb_listener.front_end.arn
  priority     = 100

  action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.api_tg.arn
  }

  condition {
    path_pattern { values = ["/api/*"] }
  }
}