These VCL functions are supported by Fastly.
Fastly provides several functions in VCL for cryptographic- and hashing-related purposes. It is based very heavily on Kristian Lyngstøl's digest vmod for Varnish 3 (which means you can also refer to that documentation for more detail).
By default VCL includes the
now variable, which provides the current time (for example,
Wed, 17 Sep 2025 23:19:06 GMT). Fastly adds several new Varnish variables and functions that allow more flexibility when dealing with dates and times.
Fastly has added several miscellaneous features to Varnish that don't easily fit into specific categories.
Fastly exposes a number of functions that support the insertion of random strings, content cookies, and decisions into requests.
Fastly has added several variables that expose information about the TLS and HTTP/2 attributes of a request.
The universally unique identifier (UUID) module provides interfaces for generating and validating unique identifiers as defined by RFC4122. Version 1 identifiers, based on current time and host identity, are currently not supported.