Utility Functions

now()

Returns the current datetime. Accepts a timeZone argument:

{{ now() }}
{{ now(timeZone="Europe/Paris") }}

max() and min()

Returns the largest or smallest of its arguments:

{{ max(5, 10, 15) }}
{# output: 15 #}
{{ min(5, 10, 15) }}
{# output: 5 #}

range()

Generates a list of integers up to and including end. The step defaults to 1:

{{ range(0, 3) }}
{# output: [0, 1, 2, 3] #}
{{ range(0, 6, 2) }}
{# output: [0, 2, 4, 6] #}

uuid()

Generates a UUID in URL-safe base62 encoding:

{{ uuid() }}

id()

Generates a short unique ID using Kestra’s internal ID utility:

{{ id() }}

ksuid()

Generates a K-Sortable Unique Identifier (timestamp-prefixed, base62-encoded). Useful when sort order by creation time matters:

{{ ksuid() }}

nanoId()

Generates a NanoID. length defaults to 21 and alphabet defaults to alphanumeric plus -_:

{{ nanoId() }}
{{ nanoId(length=10) }}

randomInt()

Generates a random integer. The upper bound is excluded:

{{ randomInt(1, 10) }}
{# generates a random integer from 1 to 9 (10 is excluded) #}

randomPort()

Picks an available local port. Useful in test or dev container flows:

{{ randomPort() }}

http()

Fetches a remote payload directly from an expression:

{{ http(uri = 'https://dummyjson.com/products/categories') | jq('.[].slug') }}

Use it sparingly. It is convenient for dynamic dropdowns and lightweight lookups, but task-level HTTP calls are usually easier to observe and retry.

fileSize()

Returns the size in bytes of a file from internal storage:

{{ fileSize(outputs.download.uri) }}

fileExists()

Returns true if the file exists:

{{ fileExists(outputs.download.uri) }}

isFileEmpty()

Returns true if the file has no content:

{{ isFileEmpty(outputs.download.uri) }}