Dynamic Variables

Dynamic variables generate a fresh value every time a request is sent. No environment setup is required. Type {{$ in any field, including the body editor, to see the autocomplete list.

Syntax

Dynamic variables use a $namespace.method format with optional comma-separated arguments:

{{$uuid.v4}}
{{$timestamp.iso}}
{{$random.int, 1, 100}}
{{$hash.sha256, my-value}}
{{$encode.base64, user:password}}
{{$faker.email}}
{{$prompt.apiKey}}
{{$file.read, /path/to/data.json}}

UUID

Variable	Output
{{$uuid.v4}}	Random UUID v4: 550e8400-e29b-41d4-a716-446655440000
{{$uuid.v7}}	Time-ordered UUID v7 (monotonically increasing)

Use {{$uuid.v4}} for random IDs and {{$uuid.v7}} when you need UUIDs that sort by creation time.

Timestamps

Variable	Output
{{$timestamp.unix}}	Seconds since epoch: 1706886400
{{$timestamp.millis}}	Milliseconds since epoch: 1706886400000
{{$timestamp.iso}}	ISO 8601: 2024-02-02T12:00:00.000Z
{{$timestamp.offset, 30, m}}	Unix seconds 30 minutes from now
{{$timestamp.offset, -1, d}}	Unix seconds 1 day ago
{{$timestamp.format, YYYY-MM-DD}}	Formatted date: 2024-02-02

Offset units: s (seconds), m (minutes), h (hours), d (days).

Format tokens: YYYY (year), MM (month), DD (day), HH (24h hour), mm (minute), ss (second).

Random Data

Variable	Output
{{$random.int}}	Integer 0–1000
{{$random.int, 1, 100}}	Integer between 1 and 100
{{$random.number, 0.5, 9.5}}	Float with 2 decimal places
{{$random.string}}	16-character alphanumeric string
{{$random.string, 32}}	32-character string (1–256)
{{$random.bool}}	true or false
{{$random.enum, dev, staging, prod}}	Random pick from the list
{{$random.name}}	Random full name: Jennifer Garcia
{{$random.email}}	Random email: jennifer.garcia482@example.com

$random.int produces integers. $random.number produces floats when either bound is a float.

Hashing

All hash variables take the input value as the first argument:

Variable	Algorithm
{{$hash.md5, input}}	MD5 (hex string)
{{$hash.sha1, input}}	SHA-1 (hex string)
{{$hash.sha256, input}}	SHA-256 (hex string)
{{$hash.sha512, input}}	SHA-512 (hex string)

HMAC variants take input and key:

Variable	Algorithm
{{$hmac.md5, input, key}}	HMAC-MD5
{{$hmac.sha1, input, key}}	HMAC-SHA1
{{$hmac.sha256, input, key}}	HMAC-SHA256
{{$hmac.sha512, input, key}}	HMAC-SHA512

Combine with environment variables for signing:

X-Signature: {{$hmac.sha256, {{requestBody}}, {{API_SECRET}}}}

Encoding and Decoding

Variable	Description
{{$encode.base64, input}}	Base64 encode
{{$encode.base64url, input}}	Base64url encode (URL-safe, no padding)
{{$encode.url, input}}	URL percent-encode
{{$encode.html, input}}	HTML entity encode (< → &lt;)
{{$decode.base64, input}}	Base64 decode
{{$decode.url, input}}	URL percent-decode

String Operations

Variable	Description
{{$regex.match, input, pattern, flags}}	First match of pattern in input
{{$regex.replace, input, pattern, replacement, flags}}	Replace pattern in input with replacement
{{$json.escape, input}}	Escape a string for safe embedding in a JSON value
{{$json.minify, input}}	Minify a JSON string (remove whitespace)

Mock Data (Faker)

Generate realistic fake data powered by Faker. All values are random and change on every send.

Person

Variable	Example output
{{$faker.firstName}}	Sarah
{{$faker.lastName}}	Johnson
{{$faker.fullName}}	Sarah Johnson
{{$faker.jobTitle}}	Senior Software Engineer
{{$faker.gender}}	Female
{{$faker.prefix}}	Dr.

Internet

Variable	Example output
{{$faker.email}}	sarah.johnson@example.com
{{$faker.username}}	sarah_j92
{{$faker.url}}	https://example.com
{{$faker.ip}}	192.168.1.42
{{$faker.ipv6}}	2001:0db8:85a3::8a2e:0370:7334
{{$faker.mac}}	00:1A:2B:3C:4D:5E
{{$faker.password}}	xK9$mP2vL
{{$faker.userAgent}}	Mozilla/5.0 (Windows NT 10.0; ...)

Location

Variable	Example output
{{$faker.city}}	San Francisco
{{$faker.country}}	Canada
{{$faker.countryCode}}	CA
{{$faker.state}}	California
{{$faker.streetAddress}}	742 Evergreen Terrace
{{$faker.zipCode}}	94107
{{$faker.latitude}}	37.7749
{{$faker.longitude}}	-122.4194
{{$faker.timeZone}}	America/New_York

Finance

Variable	Example output
{{$faker.creditCard}}	4532015112830366
{{$faker.iban}}	DE89370400440532013000
{{$faker.currencyCode}}	USD
{{$faker.currencyName}}	US Dollar
{{$faker.amount}}	42.99
{{$faker.bitcoinAddress}}	1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa

Text and Data

Variable	Example output
{{$faker.uuid}}	550e8400-e29b-41d4-a716-446655440000
{{$faker.boolean}}	true
{{$faker.word}}	synergy
{{$faker.words}}	innovative digital platform
{{$faker.sentence}}	The quick brown fox jumps over the lazy dog.
{{$faker.paragraph}}	A full paragraph of lorem-style text
{{$faker.slug}}	innovative-digital-platform

Other

Variable	Example output
{{$faker.phone}}	+1-555-0123
{{$faker.company}}	Acme Corp
{{$faker.colorHex}}	#e04f2b
{{$faker.colorName}}	cerulean
{{$faker.imageUrl}}	A random image URL
{{$faker.avatar}}	A random avatar URL

Tip

Type {{$faker. to see the full list in autocomplete. Over 60 faker functions are available.

Prompt at Send Time

Prompt the user for a value when the request is sent. The value is used once and not saved.

Variable	Description
{{$prompt.keyName}}	Shows a dialog prompting for “keyName” before sending

When a request contains $prompt variables, a dialog appears before the request is sent with an input field for each unique key. If the same key appears multiple times, only one field is shown.

{
  "token": "{{$prompt.apiToken}}",
  "environment": "{{$prompt.targetEnv}}"
}

• Cancel aborts the request. Nothing is sent.
• Multiple keys are collected in a single dialog.
• Values are not stored anywhere. They are discarded after the request completes.

File Read

Read file content at send time and substitute it inline.

Variable	Description
{{$file.read, /path/to/file.txt}}	Replaced with the file’s text content

Use this to inject certificates, configuration files, or large payloads without pasting them into the editor.

Authorization: Bearer {{$file.read, /home/user/.secrets/token.txt}}

{
  "config": {{$file.read, C:/projects/config.json}}
}

If the file cannot be read (not found or permission error), the token is left unresolved and a warning is logged to the console.

Examples

Generate a Basic auth header:

Authorization: Basic {{$encode.base64, {{USERNAME}}:{{PASSWORD}}}}

Create an expiring token timestamp:

{
  "issued_at": "{{$timestamp.unix}}",
  "expires_at": "{{$timestamp.offset, 1, h}}"
}

Sign a webhook payload:

X-Hub-Signature-256: sha256={{$hmac.sha256, {{body}}, {{WEBHOOK_SECRET}}}}

Generate test data for a user creation request:

{
  "id": "{{$uuid.v4}}",
  "name": "{{$random.name}}",
  "email": "{{$random.email}}",
  "role": "{{$random.enum, admin, editor, viewer}}",
  "createdAt": "{{$timestamp.iso}}"
}

Generate realistic fake data with Faker:

{
  "id": "{{$faker.uuid}}",
  "name": "{{$faker.fullName}}",
  "email": "{{$faker.email}}",
  "phone": "{{$faker.phone}}",
  "address": "{{$faker.streetAddress}}, {{$faker.city}}, {{$faker.country}}",
  "bio": "{{$faker.sentence}}"
}

Prompt for credentials at send time:

Authorization: Bearer {{$prompt.apiToken}}

Inject a file as the request body:

{{$file.read, /path/to/payload.json}}