Variables let you store tokens, identifiers and other values from responses and then use them later in other requests. They form the backbone that connects various tools in Proxygen together.

Environments

Open Variables window with keyboard shortcut shift-command-v.

On the left you have a list of Environments, each with its own variables. One of them is the Active Environment. When substituting values the variable name is searched first from the active and then from the Default environment.

You can set up the same variable name in several environments, with different values. For example, configure a variable named apiKey in both Development and Staging environments. Then change the active environment to use a different API key for all requests.

Placeholders

Variables can be inserted using {{name}} syntax with the variable name. They are supported in requests in the Test and Editor tools, and in Authentication and Rewrites rule fields. Type {{ to see completions of variables from active environment and available built-ins.

All placeholders are substituted with current variable values before the request is sent.

Built-ins

The following Built-in variables area available:

Name Description
uuid Inserts a random UUID value.
timestamp Inserts current timestamp e.g. 1775143329.
timestampMs Inserts current timestamp in milliseconds.
date('yyyy-MM-dd') Inserts current time in given format e.g. 2026-04-02.

For example, type {{uuid}} or {{timestamp}} in your request.

Operations

Variables and built-ins can be transformed using dot syntax with the following Operations.

Encoding and decoding

Name Description
base64Encode Base64 encode.
base64Decode Base64 decode.
base64UrlEncode Base64URL encode.
base64UrlDecode Base64URL decode.
base32Encode Base32 encode.
base32Decode Base32 decode.
base58Encode Base58 encode.
base58Decode Base58 decode.
hexEncode Hex encode.
hexDecode Hex decode.
asciiHexEncode ASCII hex encode.
asciiHexDecode ASCII hex decode.
urlEncode URL encode.
urlEncodeAll URL encode every byte.
urlDecode URL decode.
queryEncode Query parameter encode.
headerEncode HTTP header encode.
jsonEscape JSON escape.
jsonUnescape JSON unescape.
jsStringEscape JS string escape.
jsStringUnescape JS string unescape.
htmlEscape HTML escape.
htmlUnescape HTML unescape.
htmlDecimalEntityEncode HTML decimal entity encode.
htmlHexEntityEncode HTML hex entity encode.
cssEscape CSS escape.
cssUnescape CSS unescape.
octalEscape Octal escape.
octalUnescape Octal unescape.
hexEscape Hex \xNN escape.
hexUnescape Hex \xNN unescape.
unicodeEscape Escape non-ASCII as \uXXXX.
unicodeUnescape Unescape non-ASCII from \uXXXX.
quotedPrintableEncode Quoted-printable encode.
quotedPrintableDecode Quoted-printable decode.
utf7Encode UTF-7 encode.
utf7Decode UTF-7 decode.
samlEncode SAML deflate + Base64 encode.
samlDecode SAML Base64 + inflate decode.

Hashing

Name Description
sha1 SHA-1 hash.
sha224 SHA-224 hash.
sha256 SHA-256 hash.
sha384 SHA-384 hash.
sha512 SHA-512 hash.
md5 MD5 hash.
md4 MD4 hash.

String and collection

Name Description
uppercase Uppercase.
lowercase Lowercase.
trim Trim whitespace.
reverse Reverse a string.
first First element of array.
last Last element of array.
count
length		 Length of array or string.

Formatting

Name Description
jsonPrettyPrint Pretty print JSON.
xmlPrettyPrint Pretty print XML.

Some operations accept parameters:

Name Description
split('separator') Split string into array.
nth(index) Element at index (0-based).
replace('match','replacement') Literal string replacement.
regexReplace('pattern','replacement') Regex replacement.
substring(start,end) Extract portion of string.
addPrefix('text') Prepend string.
addSuffix('text') Append string.
jsonPath('query') JSONPath query.
xpath('query') XPath query.
hmacMd5('key')
hmacSha1('key')
hmacSha256('key')
hmacSha384('key')
hmacSha512('key')		 HMAC signing.

Here are some examples of chaining operations:

// Base64-encode a token and add the Bearer prefix
Authorization: {{apiToken.base64Encode.addPrefix('Bearer ')}}

// URL-encode a JSON-escaped value
body={{payload.jsonEscape.urlEncode}}

// get the second path segment from a URL stored in a variable
{{apiPath.split('/').nth(1).uppercase}}

// add a prefix to a base64-encoded value
{{secret.base64Encode.addPrefix('Basic ')}}

// extract a field from a JSON variable using jsonPath, then trim whitespace
{{response.jsonPath('$.data.name').trim}}

Scripting

Variables are also available to scripting. You can use the following functions to read from and write to variables:

// get variable value by name
getVariable(name)

// set variable value by name
setVariable(name, value)