Kong vs Varnish: What are the differences?

Introduction:

Kong and Varnish are both popular open-source solutions used in web infrastructure for different purposes. While Kong is an API gateway that acts as a middleware between clients and servers, Varnish is a web application accelerator that speeds up the delivery of content. Let's explore the key differences between Kong and Varnish.

1. Architecture: Kong operates as a reverse proxy with a plugin-based architecture, which allows for extensibility and customization of API management functionalities. On the other hand, Varnish is a caching HTTP reverse proxy that focuses primarily on improving the performance and scalability of web applications. It excels at caching and accelerating content delivery through efficient memory utilization.

2. Functionality: Kong primarily serves as an API gateway and offers features such as rate limiting, authentication, routing, and security. It enables the creation, deployment, and management of APIs in a centralized manner. Varnish, on the other hand, is focused on caching and content acceleration. It stores and serves copies of web pages to users, reducing the load on backend servers and enhancing user experience.

3. Deployment: Kong can be deployed as a standalone application or as a distributed system with multiple instances running concurrently. It can also be installed on-premises or hosted in the cloud. Varnish, however, is typically deployed as a reverse proxy in front of web servers, integrated into the infrastructure stack. It requires configuration to specify which backend servers should be accelerated.

4. Caching Mechanism: Kong does not have built-in caching capabilities. It is mainly designed to manage communication between clients and APIs. Varnish, on the other hand, has advanced caching capabilities, with a powerful configuration language that allows fine-grained control over cache rules. It can cache entire web pages or specific parts of them, reducing the load on backend servers and improving response times.

5. Scalability and Performance: Kong is known for its scalability and can handle high API traffic loads. It provides features like load balancing and service discovery, allowing for horizontal scaling and redundancy. Varnish, being highly focused on performance, can cache and serve content from memory swiftly, making it ideal for websites with high traffic and dynamic content.

6. Community Support: Both Kong and Varnish have a strong and active community of users and contributors. Kong benefits from being built on top of the Nginx web server, which has a large user base and extensive community support. Varnish, on the other hand, has been around for a longer time and has a dedicated community that contributes to its development and maintains a vast knowledge base.

In summary, Kong and Varnish differ in their architecture, functionality, caching mechanisms, deployment options, scalability, and community support. While Kong focuses on providing API management capabilities, Varnish is geared towards caching and accelerating web content delivery.