Variables overview

Variables give you more control over your configuration. They provide more flexibility when using existing advanced metadata through the use of input/output variables. Create complex properties without the need to implement advanced metadata.

Variables allow you to:

  • Make a complex forward path modification

  • Select origin based on a pattern

  • Read, add, and modify HTTP headers and cookies

  • Input to advanced metadata

  • Output from advanced metadata to drive further behaviors


Variable support is available for certain products. If you do not see variable support listed as an available module for a product, contact your account representative to learn more.

You must create a user-defined variable before you can use it in a behavior.

Notes and restrictions

  • A value has a maximum size limit of 8k per variable. Using advanced metadata, the size limit is 16k. Contact your account support representative for help configuring advanced metadata.

  • Variable support includes request-stage built-in variables only. For information or assistance with variables form any other stage, contact your account support representative.

  • Variable support does not currently distinguish our parent edge servers from our child edge servers. If you need to distinguish between these types of servers, for instance to implement a different functionality, contact your support representative.

Variable types

There are two types of variables. Built-in variables that are read-only variables that address common information about each request, and user-defined variables that you can create, edit, or otherwise modify.

Behaviors that support variables

Many Property Manager behaviors have additional fields that support the use of variables. Fields that accept variable input have the "V" icon next to them. The following behaviors accept variables:

  • Construct Response

  • Modify Incoming Request Header

  • Modify Incoming Response Header

  • Modify Outgoing Request Header

  • Modify Outgoing Response Header

  • Modify Outgoing Request Path

  • Origin Base Path

  • Origin Server

  • Redirect

  • Redirect Plus

  • Set Response Cookie

  • Set Variable

  • Site Failover


Use the following syntax in any of the behaviors that allow variable support.


Where variable type is either "built-in" or "user".

The built-in variables correspond to underlying metadata variables, typically prefixed with AK_. For instance,{{builtin.AK_PATH}}corresponds to the %(AK_PATH)metadata variable.

The user variables are prefixed with PMUSER_in the underlying metadata, for instance, {{user.PMUSER_FOO}}corresponds to %(PMUSER_FOO)in metadata syntax.

Here is an example variable expression syntax that includes a builtin variable, a fixed string, and a user defined variable: