Let’s break down this comparison into their respective features, pros, and cons as web servers, reverse proxies, and load balancers. We want to cover the best scenarios where each may be a better fit.

NGINX:

Nginx is a top-rated, open-source software used as a web server, reverse proxy and load balancer.

Main Features:

  1. HTTP and HTTPS support.
  2. Static content delivery (HTML, CSS, JS, Images, etc.).
  3. SSL and TLS support.
  4. Load balancing.
  5. Reverse proxy with caching.
  6. HTTP/2 support with backward compatibility.
  7. Gzip compression and decompression.
  8. Access and error logging.
  9. WebSockets and keep-alive connections support.

Pros:

  1. High performance: Nginx is known for its high performance and low memory footprint.
  2. Scalability: It can handle tens of thousands of simultaneous connections.
  3. Configuration: It allows for high customization through its configuration files.
  4. Wide adoption: Due to its long existence, there’s a large community and plenty of resources for troubleshooting and learning.
  5. Multi-purpose: It is a web server, reverse proxy and load balancer.

Cons:

  1. Configuration complexity: While powerful, Nginx’s configuration can be complex and hard to manage for large setups.
  2. Dynamic configuration: Nginx lacks native support for dynamic configuration or service discovery. It needs to be manually reloaded to pick up changes.
  3. Lack of native clustering support: Nginx doesn’t provide native support for clustering or maintaining states across multiple instances.

Traefik:

Traefik is a modern HTTP reverse proxy and load balancer that makes deploying microservices easy.

Main Features:

  1. HTTP/2 and HTTPS support.
  2. Dynamic configuration: It automatically discovers the proper configuration for your services.
  3. Load balancing: It distributes the network traffic evenly to maintain system stability.
  4. Multiple backend support: Docker, Swarm, Kubernetes, Mesos, Consul, etc.
  5. Middleware: Modify requests and responses for rate-limiting, authentication, etc.
  6. WebSockets, HTTP/2, GRPC ready.
  7. Metrics: Prometheus, Datadog, StatD, etc.
  8. Tracing: Zipkin, Jaeger.
  9. Let’s Encrypt support: Out-of-the-box automatic SSL.

Pros:

  1. Simplicity: Traefik is relatively easier to configure compared to Nginx.
  2. Dynamic reconfiguration is designed for busy environments, automatically discovering and mapping services.
  3. Microservices are compatible: It integrates smoothly with service discovery systems such as Docker, Kubernetes, etc.
  4. Modern protocols: Traefik was designed with current protocols such as HTTP/2 and GRPC in mind.
  5. Out-of-the-box metrics and tracing.

Cons:

  1. Less mature: Traefik is not as mature or widely adopted as Nginx, which can lead to fewer resources and community support.
  2. Limited as a standalone web server: While Traefik shines in dynamic environments, it’s less effective as a standalone web server for static content delivery.
  3. Complex advanced features: Some advanced features, like mirroring, can be more complicated to configure than Nginx.

Use as Reverse Proxy or Load Balancer:

  1. In static environments where the backend servers don’t change often, Nginx is a popular choice as a reverse proxy and load balancer due to its efficiency and performance.
  2. For dynamic environments (such as microservices architectures), Traefik is generally more effective because it can automatically update its configuration as services are added or removed.
  3. Nginx can also be a great fit when a high degree of customization is required in routing, handling requests, and performance tuning.
  4. Traefik can shine in scenarios where modern protocols are heavily used, and native support for HTTP/2, GRPC, automatic SSL, real-time metrics, and tracing can be beneficial.

Conclusion:

In summary, Nginx might be better for more static setups or when high customizability and performance are required. Traefik would be a better choice for dynamic, containerized environments where ease of configuration and automatic service discovery are needed. It’s worth noting that both can be used together, with Nginx serving static content as a web server and Traefik being used as a reverse proxy and load balancer.