Eureka vs Zuul: What are the differences?

Eureka and Zuul are both open-source projects developed by Netflix that are widely used in microservices-based architectures. While Eureka is a service registry and discovery server, Zuul is an edge service that serves as a gateway between clients and backend services. Let's explore the key differences between Eureka and Zuul:

1. Service Discovery: Eureka is primarily focused on service discovery, acting as a registry where microservices can register themselves and clients can locate and consume those services. On the other hand, Zuul is not involved in service discovery but rather acts as a gateway for routing and filtering requests between clients and backend services.

2. Routing and Load Balancing: Eureka does not provide built-in routing and load balancing capabilities. It mainly focuses on providing a centralized service registry. In contrast, Zuul acts as a reverse proxy and provides dynamic routing and load balancing features. It can intelligently route requests based on various factors such as load, availability, and service version.

3. API Gateway: Zuul is designed specifically as an API gateway, providing features like request and response filtering, rate limiting, authentication, and authorization. Eureka, on the other hand, does not provide these capabilities inherently. It is more focused on service discovery and registration.

4. Integration with Other Netflix Projects: Eureka integrates well with other Netflix services like Ribbon for client-side load balancing and Hystrix for fault tolerance. Zuul also integrates with these projects but offers additional features like dynamic routing based on service metadata and intelligent load balancing using Ribbon and Hystrix.

5. Protocol Support: Eureka supports both HTTP and TCP protocols for service registration and discovery. Zuul primarily uses HTTP for routing requests to backend services.

6. Scalability: Eureka is designed to be highly scalable and fault-tolerant. It can handle large-scale deployments and has built-in mechanisms for handling failovers and replication. On the other hand, Zuul can also be scaled horizontally by deploying multiple instances behind a load balancer to handle increased traffic.

In summary, Eureka and Zuul serve different purposes in microservices architectures. Eureka provides service discovery capabilities, while Zuul acts as an API gateway with routing, filtering, and load balancing features. They can be used in combination to build resilient and scalable microservices-based systems.