Reverse proxy vs API gateway vs load balancer

Reverse proxy
An API gateway is a specialized type of reverse proxy

The easiest way to differentiate them is by their core focus: a load balancer focuses on scale, a reverse proxy focuses on security and optimization, and an API gateway focuses on application logic and API management.

Direct Comparison

Feature	Reverse Proxy	Load Balancer	API Gateway
Primary Goal	Protects, caches, and isolates backend web servers.	Distributes traffic to prevent server overload.	Manages, secures, and routes individual API endpoints.
Traffic Focus	General web traffic (HTTP/HTTPS, static files).	Network layers (TCP/UDP) or application layers (HTTP).	Application APIs (REST, GraphQL, gRPC).
Typical Tools	NGINX, Apache, HAProxy	AWS ALB, F5 BIG-IP, HAProxy	Kong, Apigee, AWS API Gateway

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1. Reverse Proxy (The Shield & Booster)

A reverse proxy sits in front of a web server to shield its identity, optimize performance, and handle incoming requests. It acts as an intermediary so clients never talk directly to your actual application servers.

• Main Job: Privacy, security, and offloading repetitive tasks.
• Key Capabilities:
  • SSL/TLS Termination: It handles the heavy encryption/decryption work so backend servers don't have to.
  • Caching: It stores copies of popular static content (like images or CSS) and serves them instantly without hitting your backend.
  • Anonymity: It hides the IP addresses and structures of your internal infrastructure from the public internet.

2. API Gateway (The Smart Concierge)

An API gateway is a specialized type of reverse proxy designed specifically for modern microservices architectures. It doesn't just pass requests along; it inspects, translates, and manipulates them based on application rules.

• Main Job: Orchestrating API requests and enforcing business logic at the edge.
• Key Capabilities:
  • Request Routing / Composition: It can take a single request from a mobile app, fetch data from three separate backend microservices (e.g., Users, Inventory, and Shipping), combine the data, and send back one clean response.
  • Authentication & Authorization: It checks if a user's API token is valid before letting the request reach any microservices.
  • Rate Limiting & Throttling: It blocks users who try to spam or abuse specific endpoints (e.g., limiting a user to 60 requests per minute).
  • Protocol Translation: It can convert an incoming REST request into an internal gRPC request.

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How They Work Together

In a large production environment, you will often see all three layered together to form a robust architecture:

1. A Load Balancer sits at the very front to split incoming traffic across multiple instances.
2. The traffic hits a Reverse Proxy to strip away SSL encryption and handle basic caching.
3. The request is passed to the API Gateway, which authorizes the user's API token and routes them to the correct backend microservice.