API Gateway vs Load Balancer: Key Differences Explained

By /

Featured Image
API Gateways and Load Balancers serve distinct purposes in cloud architectures, yet their roles are often conflated. Here’s a breakdown:

API Gateway

  • Purpose: Manages how clients access services (e.g., authentication, rate limiting, request/response transformations).
  • Use Cases:
  • REST/GraphQL API management
  • Authentication (JWT, OAuth)
  • Request throttling & caching
  • Protocol translation (HTTP → gRPC)

Load Balancer

  • Purpose: Distributes traffic across servers (where the traffic goes).
  • Use Cases:
  • High availability (failover routing)
  • Traffic distribution (round-robin, least connections)
  • SSL termination

You Should Know: Practical Implementation

1. AWS API Gateway + ALB Example

 Create API Gateway (REST API)
aws apigateway create-rest-api --name "MyAPI" --description "Demo API Gateway"

Deploy Load Balancer (ALB)
aws elbv2 create-load-balancer --name "MyALB" --subnets subnet-123456 subnet-789012 --security-groups sg-123456

2. Nginx as API Gateway

 Sample Nginx config for API routing
server {
listen 80;
server_name api.example.com;

location /auth {
proxy_pass http://auth-service;
limit_req zone=api_rate_limit burst=5;
}

location /data {
proxy_pass http://data-service;
auth_request /validate-jwt;
}
}

3. Kubernetes Ingress (Load Balancer) vs Gateway API

 Kubernetes Ingress (Layer 7 LB)
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: my-ingress
spec:
rules:
- host: myapp.com
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: my-service
port:
number: 80

Gateway API (K8s-native API Gateway)
apiVersion: gateway.networking.k8s.io/v1beta1
kind: HTTPRoute
metadata:
name: my-route
spec:
parentRefs:
- name: my-gateway
rules:
- matches:
- path:
value: "/v1/data"
filters:
- type: RequestHeaderModifier
requestHeaderModifier:
add:
- name: "X-API-Key"
value: "secret-key"

4. Testing Load Balancer Health Checks

 Check ALB health (AWS CLI)
aws elbv2 describe-target-health --target-group-arn arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/my-target-group/1234567890123456

Curl test for API Gateway
curl -X GET https://api.example.com/v1/data -H "Authorization: Bearer <JWT_TOKEN>"

What Undercode Say

  • API Gateways excel in security (OAuth, WAF) and traffic control (rate limiting).
  • Load Balancers focus on scalability (horizontal scaling) and fault tolerance (health checks).
  • Hybrid setups (e.g., API Gateway → LB → Microservices) are common in cloud-native apps.
  • K8s Gateway API is blurring the lines by unifying routing logic under GitOps.

Linux/Windows Commands for Debugging:

 Inspect HTTP headers (Linux)
curl -v http://example.com

Check open ports (Windows)
netstat -ano | findstr LISTENING

Trace API latency (Linux)
traceroute api.example.com

AWS CLI to list ALBs
aws elbv2 describe-load-balancers --query "LoadBalancers[].DNSName"

Prediction

The convergence of API Gateways and Load Balancers into unified control planes (e.g., Istio, Envoy) will dominate cloud architectures by 2025, reducing operational overhead.

Expected Output:

  • Clear distinction between traffic management (API Gateway) and traffic distribution (LB).
  • Code snippets for real-world implementation.
  • Future trend analysis.

Relevant URL: TechOps Examples Newsletter

References:

Reported By: Govardhana Miriyala – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram

Related Posts: