Variables and Functions

Syntax

Write {{name}} to insert the value of the variable name. There are no spaces inside the braces: {{baseUrl}}, not {{ baseUrl }}.

Chapar fills variables in when it sends a request, in:

the URL, query params and path params,
headers and gRPC metadata,
the body: JSON, XML, text, form fields and URL-encoded fields,
auth fields,
the gRPC server address and message,
GraphQL queries and variables.

The saved request keeps its placeholders. A variable that doesn’t exist is sent as written, {{name}} included, which makes typos easy to spot in the response of an echo endpoint.

Variables come from two places:

The active environment.
The built-in functions below, which produce a new value every time a request is sent.

Completion and hover

Type {{ in any field or editor and Chapar lists what you can insert: the variables of the active environment with their values, the built-in functions, and the values the request’s Extract rules produce.

Variable completion

Placeholders are colored: a known variable in the info color, an unknown one in the warning color. Hover one to see where it comes from and its value. Secret values are never shown.

Variable hover

Built-in functions

Function	Value	Example
`{{randomUUID4}}`	A random UUID (version 4)	`5f0c7a0e-8f6b-4d5a-9c1e-3a2b1c0d9e8f`
`{{timeNow}}`	The current time in UTC, RFC 3339	`2026-09-25T19:55:17Z`
`{{unixTimestamp}}`	The current Unix time, in seconds	`1790366117`
`{{fullDate}}`	The current time in UTC, RFC 1123 with a numeric zone	`Fri, 25 Sep 2026 19:55:17 +0000`
`{{randInt100}}`	A random integer from 0 to 99	`42`
`{{randInt1000}}`	A random integer from 0 to 999	`718`
`{{randInt}}`	A random non-negative integer	`5577006791947779410`
`{{randFloat}}`	A random number from 0 to 1, six decimals	`0.604660`
`{{randFloat32}}`	A random number from 0 to 1, six decimals	`0.940509`
`{{randBool}}`	`true` or `false`	`true`

For example, a JSON body that creates a unique record on every send:

{
  "requestId": "{{randomUUID4}}",
  "title": "Load test item {{randInt1000}}",
  "createdAt": "{{timeNow}}"
}

Don’t give your own variables the name of a function: the function wins.

Values from responses and scripts

Variables don’t have to be typed in by hand:

Request actions copy values from a response into the active environment.
Python scripts can read and write any variable with chapar.env.

Cookies Settings