Advanced Personalization with Liquid

This is a list of the Liquid filters and tags you can use in Hackle CRM campaigns. Tags and filters that are not on this list may not work, and in most cases they are converted to an empty string.

Available Variables

Through the personalization variable modal in the Dashboard, you can reference values that differ for each user.

Example: Hello {{ user_properties['name'] }}

Common Patterns

Use a default value when the name is missing

Use fallback text when a variable has no value.

Hello {{ user_properties.name | default: 'Customer' }}

→ Hello Customer (when name is missing)

Thousands separators for numbers

Display points, amounts, and similar values in a readable form.

Variable: point = 15000

→ 15,000P

Show a date in Korean time and language

Convert to Asia/Seoul and print the weekday in Korean.

Variable: ordered_at = "2026-07-15 23:00:00 UTC"

→ 07월 16일 목요일

Replace values that are too long with fallback text

Values longer than the specified length are replaced entirely.

Variable: name = "Bartholomew" (11 characters)

→ Hello Customer

Quick Reference

Filters

Tags

String Filters

append

Appends another string to the end of a string.

→ Spring breeze blows

prepend

Prepends another string to the beginning of a string.

→ falling petals

capitalize

Capitalizes the first character and leaves the rest unchanged.

→ Spring bloom

downcase

Converts all characters to lowercase.

→ blossom

upcase

Converts all characters to uppercase.

→ PETAL

lstrip

Removes whitespace from the left (beginning) of a string.

→ [sprout ]

rstrip

Removes whitespace from the right (end) of a string.

→ [ sprout]

strip

Removes whitespace from both ends of a string.

→ [sprout]

strip_html

Removes HTML tags from a string.

→ Important notice

strip_newlines

Removes newline characters from a string.

→ Summeris here

newline_to_br

Replaces newline characters with <br /> tags.

→ When the cicadas sing<br /> summer has arrived

remove

Removes every occurrence of a substring from a string.

→ night night

remove_first

Removes only the first occurrence of a substring from a string.

→ night summer night

replace

Replaces every occurrence of a substring with another string.

→ summer sky, summer sky

replace_first

Replaces only the first occurrence of a substring with another string.

→ sun-rain-rain

split

Splits a string on a delimiter to build an array. Because the result is an array, the example uses join as well.

→ sea / watermelon / shower

slice

Cuts out part of a string by start position and length.

Signature: slice: start[, length]

truncate

Shortens a string to the specified length and appends an ellipsis.

Signature: truncate: length[, ellipsis]

→ The autumn sky...

Note: the ellipsis counts toward the length — with the default ellipsis (...), the visible body is length - 3 characters, and if you specify your own ellipsis, its length is subtracted instead.

truncatewords

Shortens a string to the specified number of words and appends an ellipsis.

Signature: truncatewords: word_count[, ellipsis]

→ Leaves turn red...

escape

Escapes HTML special characters in a string.

→ <a href="x">link</a>

escape_once

Escapes HTML special characters in a string, without re-escaping parts that are already escaped.

→ <p> & <p>

Number Filters

abs

Returns the absolute value of a number.

→ 5

at_least

Returns the specified minimum if the number is smaller than it.

→ 5

at_most

Returns the specified maximum if the number is larger than it.

→ 5

ceil

Rounds a number up to an integer.

→ 2

floor

Rounds a number down to an integer.

→ 1

round

Rounds a number to the nearest value.

Signature: round: [decimal_places]

plus

Adds numbers.

→ 125

minus

Subtracts numbers.

→ 75

times

Multiplies numbers.

→ 300

divided_by

Divides numbers.

Note: dividing integers yields an integer quotient (the decimal part is dropped). If you need a decimal result, divide by a float such as 3.0.

modulo

Returns the remainder of a division.

→ 1

number_with_delimiter

Adds thousands separators (commas) to a number.

→ 1,234,567.89

Array Filters

compact

Removes nil values from an array.

→ maple,leaf

concat

Concatenates two arrays.

→ a,b,c

first

Returns the first element of an array.

→ apple

last

Returns the last element of an array.

→ chestnut

join

Joins the elements of an array with a delimiter to build a string.

→ apple, persimmon, chestnut

map

Extracts only the specified property value from each element to build a new array.

→ maple, ginkgo

reverse

Reverses the order of an array.

→ chestnut,persimmon,apple

sort

Sorts an array (case-sensitive, uppercase first).

→ Banana,Cherry,apple

Note: sort is case-sensitive (uppercase first), while sort_natural ignores case — the output above shows the difference.

sort_natural

Sorts an array without regard to case.

→ apple,Banana,Cherry

uniq

Removes duplicate values from an array.

→ a,b

where

Keeps only the elements that have the specified property value.

Signature: where: property[, value]

→ camellia

size

Returns the number of elements in an array, or the length of a string.

Date Filters

date

Converts a date/time value into a string in the specified format.

Signature: date: format[, timezone][, locale: "language_tag"]

Note:

• An ISO Z suffix on a date string is not parsed (2026-07-16T10:30:00Z ✗) — use a space-separated zone (2026-07-16 10:30:00 UTC) or a format without a zone.

• Numeric input is interpreted in epoch seconds.

• timezone supports TZ names (Asia/Seoul) and ISO offsets (+09:00), but not numeric minute offsets (360).

• An invalid timezone or locale causes only that parameter to be ignored.

• timezone (a positional argument) and locale: (a named argument) can be used together, in any order.

URL Filters

url_encode

URL-encodes a string.

→ user%40example.com

url_decode

Decodes a URL-encoded string back to its original form.

→ hello world!

url_escape

Escapes only the characters in a string that cannot be used in a URL.

→ https://example.com/search?q=hello%20world

url_param_escape

Escapes a string for use as a URL query parameter value.

→ query+A%26B

JSON Filters

json_escape

Safely escapes a string for use as a JSON string value.

→ He said \"hello\"

json_parse

Parses a JSON string into an object that can be accessed in the template.

→ Alex's points: 1500

Note: if parsing fails, the result is nil and rendering continues.

as_json_string

Serializes a value into a JSON string.

→ {"name":"Alex","point":1500}

Other Filters

default

Returns a fallback value when the value is empty or falsy.

Signature: default: default_value

→ Hello traveler

fallback_over_length

Returns fallback text when the string exceeds the specified length.

Signature: fallback_over_length: max_length, fallback_text

Note: length is measured in UTF-16 code units (the same as the size filter).

Tags

assign

Assigns a value to a variable.

→ Hello Hackle

capture

Stores the rendered result of a block in a variable.

→ Welcome, Alex

if

Renders the block only when the condition is true.

→ VIP benefits

unless

Renders the block only when the condition is false.

→ Start your subscription

case / when

Renders one of several branches depending on a value.

→ Gold benefits

for

Iterates over an array or a range, rendering the block repeatedly.

→ tangerine citron dried persimmon

break

Immediately exits a for loop.

→ 123

continue

Skips the current iteration of a for loop and moves on to the next one.

→ 1245

cycle

Outputs several values in turn, one per iteration.

→ ABAB

comment

Does not output the content inside the block.

→ beforeafter

raw

Outputs the content inside the block as-is, without interpreting Liquid syntax.

→ {{ name }} is not substituted

increment

Increments and outputs a dedicated counter that starts at 0.

→ 0-1-2

Note: increment starts at 0 and decrement starts at -1, and both use a counter that is separate from assign variables.

decrement

Decrements and outputs a dedicated counter that starts at -1.

→ -1--2

Other Tags

connected_content

Calls an external API and stores the response (JSON) in a template variable.

For detailed usage and limits (timeout, response size cap, allowed protocols and addresses, and so on), see Writing Connected Content.

Signature: {% connected_content <url> [:method <method>] [:body <body>] [:headers <json>] [:save <variable>] %}

→ Hi Alex, check out today's recommended products (assuming the API responded with {"name": "Alex"})

Note: an actual HTTP call is made at render time. The output above is an example based on the assumed response.

random

Generates and outputs a random number. Pass a positive integer to get a random integer that is 0 or greater and less than that value.