Prefixes Used with Variables

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Prefixes Used with Variables

Prefixed can precede the name of a variable beginning with version 8.1.

There are 2 kinds of prefixes:

Context prefix

Protocol prefix


Context prefix

A context prefix can have 2 values: local or global

A prefix precedes the name of a variable and ends with the "@" symbol. It is not case-sensitive.

For example:



When a context prefix is not specified, the general rules of visibility described in the chapter "Rules for Using Variables in Expressions" (see "The rule of visibility") apply.


Protocol prefix

Only one protocol, JSON, is currently used. A protocol prefix ends with a colon ":"

For example:


If a protocol prefix is not used, this means that we are using the value of the variable entirely as it is. We either extract it while reading or write the specified value.

A json prefix means that the userinfo variable should be processed as a JSON object and the value at the name.firstname destination should be extracted from it.

If you use this expression to write to a variable, RoboTask will accordingly write to the userinfo variable the value specified at the name.firstname destination as to a JSON object.

If you attempt to read just the value of the userinfo variable without prefixes, RoboTask will return the JSON object entirely in the form of a string.

For example:

{"name":{"firstname":"John","surname":"Dou"},"address":"New York, 5-th ave,125"}

Please note that the path to the value in the JSON object is case-sensitive. This is a JSON standard. In other words, the expressions



are different expressions that can contain different values.


In this way, the JSON format allows storing structured data and arrays of values.

We will skip the format description. For more information, go to the article:


Use of Prefixes

Prefixes can be used in any sequence in front of the name of a variable. Both prefixes can be used at the same time.

For example, the expressions


have the same meaning.


If you specify a wrong prefix, RoboTask will treat this sequence of characters as a part of the variable name and you will most probably get an error message.


note Related Topics

Usage of Variables

System variables

Custom variables

Local variables

Create a Variable

Add Variables to a Task

Saving of a result into a variable

Rules for using variables in expressions

How to use variables correctly

Options > Variables