NLB vs ALB

L4 vs L7.

Overview

NLB vs ALB is the AWS load balancer choice. NLB is layer 4 (TCP/UDP), ALB is layer 7 (HTTP/HTTPS); the right pick depends on whether you need L7 routing or L4 latency.

• L4 vs L7. NLB layer 4 TCP/UDP; ALB layer 7 HTTP/HTTPS; the choice follows the protocol the application speaks.
• NLB ultra-low latency. Pass-through TCP; matches latency-sensitive workloads where every millisecond counts.
• ALB HTTP-aware. Per-host, per-path routing; matches HTTP workloads with multiple services behind one LB.
• NLB static IPs plus ALB cookie stickiness. NLB static IPs are allowlist-friendly; ALB cookie stickiness supports stateful apps.

The approach

The practical approach: ALB for HTTP workloads, NLB for TCP/UDP, NLB for static-IP allowlist requirements, ALB for sticky sessions, documented choice per LB. The team’s discipline produces matched load balancing.

• ALB for HTTP. L7 routing, host and path matching; the right call for web workloads with multiple backend services.
• NLB for TCP/UDP. Layer 4 ultra-low latency; the right call for non-HTTP protocols (gRPC over TCP, custom binary).
• NLB for static IPs. Allowlist-friendly endpoint; the right call when downstream firewalls need stable source IPs.
• ALB for sticky sessions. Cookie-based stickiness; the right call for stateful applications that need session affinity.
• Document the choice. Per-LB rationale committed to the repo; supports decisions and operational reviews.

Why this compounds

NLB vs ALB discipline compounds across services. Each correct choice produces ongoing value; the team’s networking expertise grows; new services pick the right LB on the first try.

• Better performance. Right LB for the workload; the user-visible latency matches the LB’s strengths.
• Better cost efficiency. Right pricing model; NLB and ALB charge differently; the cheaper match is real.
• Better operational fit. Right LB matches existing tooling; the team’s muscle memory transfers.
• Institutional knowledge. Each LB teaches AWS networking; the team’s networking muscle grows.

NLB vs ALB is an infrastructure decision that pays off across years. Nova AI Ops integrates with LB telemetry, surfaces patterns, and supports the team’s traffic-management discipline.