Variables

Variables let you use dynamic values throughout your .rext files. They are enclosed in double curly braces: {{variableName}}.

Syntax

GET {{baseUrl}}/users
Authorization: Bearer {{token}}

Variables can be used in:

URLs — GET {{baseUrl}}/users
Headers — Authorization: Bearer {{token}}
Body — { "email": "{{email}}" }
Query parameters — @query search = {{searchTerm}}

Variable Resolution Order

When Rext encounters a {{variableName}}, it resolves the value from these scopes, in order:

Built-in ($) — Dynamic variables generated at runtime
Session — Variables captured during the current session
Collection — Variables scoped to the current collection
Environment — Variables from the active environment file (rext.env.json)
Global — Variables available across all files and sessions

Built-in Dynamic Variables

Built-in variables start with $ and generate a new value each time a request is executed. Each occurrence produces a unique value — two {{$uuid}} in the same request generate two different UUIDs.

Timestamps

Variable	Description	Example
`{{$timestamp}}`	Unix epoch (seconds)	`1740583516`
`{{$timestampMs}}`	Unix epoch (milliseconds)	`1740583516000`
`{{$isoTimestamp}}`	ISO 8601 UTC	`2026-02-26T15:35:16.000Z`
`{{$localTimestamp}}`	Local date/time	`2026-02-26 11:35:16`

Date Formatting

Variable	Description	Example
`{{$date}}`	Local date YYYY-MM-DD	`2026-02-26`
`{{$date:DD/MM/YYYY}}`	Custom format	`26/02/2026`
`{{$date:HH:mm:ss}}`	Time only	`11:35:16`
`{{$date:DD-MMM-YYYY}}`	Abbreviated month	`26-Feb-2026`
`{{$date:+7:YYYY-MM-DD}}`	Offset (+/- days)	`2026-03-05`

Supported tokens: YYYY, MM, DD, HH, mm, ss, SSS, MMM (abbreviated), MMMM (full month name).

UUIDs

Variable	Description	Example
`{{$uuid}}`	UUID v4 (random)	`a1b2c3d4-e5f6-4a7b-...`
`{{$guid}}`	Alias for `$uuid`	`a1b2c3d4-e5f6-4a7b-...`
`{{$uuidV1}}`	UUID v1 (timestamp)	`6fa459ea-ee8a-1a3e-...`

Random Generators

Variable	Description	Example
`{{$randomInt}}`	Integer 0–1000	`742`
`{{$randomInt:1:100}}`	Integer in range	`37`
`{{$randomFloat}}`	Float 0–1 (2 decimals)	`0.73`
`{{$randomFloat:1:100:4}}`	Float with precision	`42.8193`
`{{$randomString}}`	Alphanumeric (16 chars)	`aB3xK9mP2qR7wT1s`
`{{$randomString:32}}`	Custom length	`aB3xK9mP...`
`{{$randomHex:8}}`	Hexadecimal string	`a3f2b1c0`
`{{$randomEmail}}`	Random email	`user-a3f2b@rext.dev`
`{{$randomBoolean}}`	`true` or `false`	`true`

Enum (Pick from List)

Variable	Description	Example
`{{$enum:a,b,c}}`	Random from list	`b`
`{{$enum:pending,active,closed}}`	API enums	`active`
`{{$enum:"hello, world","bye",ok}}`	Quoted values (with commas)	`hello, world`

Metadata

Variable	Description	Example
`{{$env}}`	Active environment name	`Production`

Complete Example

POST {{baseUrl}}/api/orders
Content-Type: application/json

{
  "id": "{{$uuid}}",
  "timestamp": {{$timestamp}},
  "deliveryDate": "{{$date:+30:YYYY-MM-DD}}",
  "priority": {{$randomInt:1:5}},
  "status": "{{$enum:pending,processing,shipped}}",
  "environment": "{{$env}}",
  "contactEmail": "{{$randomEmail}}"
}

Setting Variables

Variables can be set in two ways:

1. Environment Files

Define variables in rext.env.json:

{
  "Development": {
    "baseUrl": "http://localhost:3000",
    "apiKey": "dev-key-123"
  },
  "Production": {
    "baseUrl": "https://api.production.com",
    "apiKey": "prod-key-456"
  }
}

See Environment Files for details.

2. Variable Capture

Extract values from responses using @capture:

@name Login
POST {{baseUrl}}/auth/login

@capture token = body.access_token

See Variable Capture for details.

Next Steps

Set up Environment Files
Learn about Variable Capture