Fastly vs Varnish: What are the differences?

Introduction

In this article, we will compare two popular content delivery networks (CDNs) - Fastly and Varnish. While both Fastly and Varnish offer similar functionalities in terms of caching and content delivery, there are some key differences that set them apart.

1. Architecture: Fastly and Varnish differ in their architecture. Fastly operates in a distributed server model, with multiple Points of Presence (PoPs) spread out across the globe. This helps to ensure low latency and high availability. On the other hand, Varnish is a reverse caching proxy that runs on a single server or a cluster of servers.

2. Ease of Use: Fastly provides a user-friendly and intuitive web interface, making it easier for users to manage their CDN configurations. It offers a well-documented API that allows for seamless integration with various development tools and platforms. Varnish, on the other hand, requires more technical expertise to set up and configure as it primarily relies on configuration files and VCL (Varnish Configuration Language).

3. Advanced Caching Capabilities: Fastly offers advanced caching capabilities such as Edge Side Includes (ESI), which allows for fragment caching and dynamic content assembly. It also provides surrogate keys that enable granular cache invalidation. Varnish, on the other hand, offers powerful caching features through its flexible VCL configuration, enabling developers to define complex caching rules and logic.

4. Pricing Model: Fastly follows a usage-based pricing model, where customers pay for the amount of bandwidth consumed and requests processed. They also have various pricing tiers based on the level of support and additional features required. On the other hand, Varnish follows an open-source model and is free to use, with optional commercial support available. This makes Varnish a cost-effective option for organizations with limited budgets.

5. Support and Documentation: Fastly provides comprehensive documentation, support through various channels like email, chat, and phone, as well as a community forum where users can share knowledge and seek assistance. Varnish also has good documentation and an active community, but official support from Varnish Software requires a commercial license.

6. Integration and Ecosystem: Fastly integrates well with various third-party services and tools, including popular content management systems and developer platforms. It also provides a Marketplace with pre-built solutions and configurations. While Varnish also has integrations with several platforms and extensions developed by the community, its ecosystem may be comparatively smaller than Fastly's.

In summary, Fastly and Varnish have several key differences. Fastly operates in a distributed server model and provides a user-friendly interface, while Varnish runs on a single server or cluster and requires more technical expertise. Fastly offers advanced caching capabilities, follows a usage-based pricing model, and provides comprehensive support. In contrast, Varnish is free and open-source, has a flexible configuration language, and has a smaller ecosystem.