Reference documentation

Welcome to the Fastly reference library. Here you'll find comprehensive technical detail about the interfaces exposed by the Fastly platform and products, including complete syntax and examples for functions, variables, CLI commands, and API endpoints.

API

Via the Fastly API you can perform any of the operations that are possible within the management console, including creating services, domains, and backends, configuring rules or uploading your own application code, as well as account operations such as user administration and billing reports.

VCL

Our edge cloud platform evolved from Varnish 2.1.5 and supports a heavily modified and extended variant of Varnish Configuration Language (VCL) for programming custom, high performance edge logic on our VCL services.