Fastly VCL: A Comprehensive Guide

This guide provides detailed documentation on how to write a Fastly VCL service, explaining how Fastly VCL works, the HTTP request pipeline, and real-world examples.

Table of Contents

1. Introduction to Fastly VCL
2. The HTTP Request Pipeline
3. VCL Basics
4. Backend Configuration
5. Caching Strategies
6. Real-World Examples

📚 Complete VCL Function Reference

For a comprehensive reference of ALL Fastly VCL functions, see the vcl-functions directory. This essential reference contains detailed documentation for every function available in Fastly VCL, including parameters, return values, and usage examples.

The function reference is a critical companion to this guide and should be consulted frequently when developing VCL code.

What is Fastly VCL?

Fastly VCL (Varnish Configuration Language) is a domain-specific language used to configure Fastly's edge cloud platform. It's based on the open-source Varnish Cache language but includes Fastly-specific extensions and features.

With Fastly VCL, you can:

• Control how requests and responses are processed
• Define caching behavior
• Implement content-based routing
• Perform edge-based transformations
• Implement security policies
• And much more

This documentation will help you understand how to leverage Fastly VCL to build powerful, efficient edge computing solutions.