Personalizing messages with Liquid

Liquid is a templating language that lets you personalize messages based on your audience’s data. Any part of your message can contain liquid, meaning that you’re not just limited to personalized message content: you can use liquid to personalize your sender information, email subjects, and so on.

 New to liquid? Check out our tutorial for marketers!

Our tutorial here can help you understand the fundamentals of message personalization and how to use your data to send engaging messages that increase conversion rates.

How it works

Liquid lets you use variables and other logical statements in messages. These can be customer attributesA key-value pair that you associate with a person—like their name, the date they were created in your workspace, etc. Use attributes to target people and personalize messages., event data, and so on. When we send a message (commonly called a deliveryThe instance of a message sent to a person. When you set up a message, you determine an audience for your message. Each individual “send”—the version of a message sent to a single member of your audience—is a delivery.), we process the liquid syntax in your messages, generating a message personalized for the individual recipient.

For example, if you store a person’s first name as an attribute called first_name, you can reference a person’s name as {{customer.first_name}}. Then, whenever you send that message to a person, we’ll use that person’s first name in the message.

If your liquid statements don’t evaluate properly—like, if a person didn’t have a first_name attribute from our example above—a message won’t render, and we’ll log a Failed state for that message. To get around these kinds of issues, you can add fallback statements and other logic in your liquid syntax that determines what to render when someone doesn’t have a variable.

We have an example of a fallback statement to make sure that your message renders even if a person doesn’t have a first_name attribute.

{% if customer.first_name %}
   Hi {{customer.first_name}}!
{% else %}
   Hi Buddy!
{% endif %}
flowchart LR a["message with
{{customer.first_name}}"] a-->b{Does customer have
first_name attribute?} b-->|yes|c[Hi Alex!] b-->|yes|d[Hi Blair!] b-.->|no|e{Is there a fallback?} e-->|yes|f[Hi Buddy!] e-.->|no|g[Message failure] style c fill:#B5FFEF,stroke:#007069 style d fill:#B5FFEF,stroke:#007069 style f fill:#B5FFEF,stroke:#007069 style g fill:#FFC4CF,stroke:#69002C

Liquid personalization variables

While you can access a lot of information with Liquid, there are generally three types of variables you’ll use to personalize messages for your audience: attributes, event properties, and trigger properties.

  • attributes use the customer scope—{{customer.<attribute_name>}}; these are our most common variables, and they’re available in almost every context.
  • event properties from the data object in an event that triggers a campaign use the event scope—{{event.<>}}
  • trigger properties This is data from an incoming webhook that triggers your campaign, or the data object in a transactional message or API-triggered broadcast—{{trigger.<>}}

You can reference attributes (using the customer scope) in any message. You can only use event properties in a campaign that uses a trigger event and trigger properties in an API-triggered broadcast or transactional message.

When you create a message, we show a Sample data section with representative attribute and event or trigger property examples that you can use to personalize your message.

 You can also access meta variables about campaigns, messages, etc

We expose a number of meta variables—variables about a message itself—that you can use with Liquid. You probably don’t want to expose these to your audience, but it’s possible that you might use them

Attribute variables

The {{customer.<var>}} scope represents attributes associated with people. You can reference customer variables in any message or action except when working with anonymous events.

If you want to include a dynamic customer attribute, you’ll want to include the tag that references that attribute. For example, if someone has an attribute on their profile called first_name, the tag would be: {{ customer.first_name }}.

As you can see, anything you’ve included as a customer attribute should start with customer. before your attribute name. If you’ve got country, for example, it’d be {{ }}

Event data variables

Let’s use a simple example: imagine one of your customers bought a pair of socks, and you want to send them a receipt for those socks. To do that, you send a purchase event, with data for the socks they bought, and how much those socks cost. Say the data that received looks like this (JavaScript):

_cio.track("purchase", { price: "23.45", product: "socks" });

You could then use that data in your message content (be it email, push, in-app, or anything else) like this:

You just bought {{ event.product }} for {{ event.price }}!

This outputs “You just bought socks for 23.45!” You’ll see that though the event is named “purchase”, you still use the notation event to reference it in your message.

Outside of the event scope, which represents the data from your event, you can also access meta information about the event.

  • event_name represents the event name, as sent into
  • event_id represents the ID as logged by; this value is always unique.
  • event_timestamp is the event timestamp in Unix epoch format.

 You can only use data from the event that triggered your campaign

Even if you reference other events in your campaign—like with a wait, or as a conversion condition, you can only use properties from the event that triggered your campaign in liquid. You can’t reference an outside event.

Trigger properties

When you send an API-triggered broadcast, a transactional message, or use liquid to access properties in an incoming webhook from a Data campaign, you reference properties from the trigger event as {{trigger.<property>}}.

For example, if your transactional message is designed to send shipping updates, you might include information about the item(s) that you’re shipping to your audience and when they’ll arrive, like this:

Your {{trigger.product}} has shipped! It will arrive in {{trigger.minShipTime}} to {{trigger.maxShipTime}} {{trigger.unitOfTime}}.

And you could expect that to output, “Your trampoline as shipped! It will arrive in 4 to 6 weeks.”

See API-triggered broadcasts and transactional messages for more information.

JSON notation and liquid

Liquid uses JSON dot notation to access nested variables. If you’re new to JSON and organizing data, check out our introduction to JSON. But, all this means is that you can store and access nested properties in liquid!

For example, imagine that someone refers a customer to you, and you store that referral as an attribute. You might have an attribute called referrer that contains information like, how the referring party is related to the new customer, etc.

You could access those nested properties with {{customer.referrer.relationship}} or

json attribute example
json attribute example

Liquid Fallbacks

Messages will fail if you attempt to use data that does not exist—like when person doesn’t have an attribute or an event doesn’t have a property you reference. To prevent this kind of error, you should implement an if statement to fallback to a static value when a variable (attribute, event property, etc) doesn’t exist.

Here’s Brendan showing how to do this the easy way when you add attributes from our sidebar. Brendan’s demonstration works everywhere except the Drag and Drop email editor. In the drag and drop editor, you’ll need to add your own liquid, as explained below.

You can also write your own fallback statements using liquidA syntax that supports variables, letting you personalize messages for your audience. For example, if you want to reference a person’s first name, you might use the variable {{customer.first_name}}.. For example, a subset of people have a value for an attribute named plan_name, you could create a fall back like this:

{% if customer.plan_name != blank %}
  You are currently on our {{ customer.plan_name | capitalize }} plan.
{% else %}
  Please choose a plan.
{% endif %}

That will show, "You are currently on our XYZ plan." for People who have a value for their plan_name attribute and "Please choose a plan." for People who do not have a value for their plan_name attribute.

Alternatively, if you would rather not show anything for People who do not have a value for their plan_name attribute you can just leave off the else statement like this:

{% if customer.plan_name != blank %}
  You are currently on our {{ customer.plan_name | capitalize }} plan.
{% endif %}

That will show, "You are currently on our XYZ plan." for People who have a value for their plan_name attribute and nothing at all for People who do not have a value for their plan_name attribute.

Liquid message meta variables

If you want to personalize messages for an audience of people, you’re probably looking for Personalization variables above.

When we render messages—when you preview a message or we generate a delivery—we produce meta-information about your message, campaign, etc that you can reference with liquid. These variables generally aren’t meaningful to your audience. You would not want to expose them in a message, but you might use them programmatically to construct custom unsubscribe links, etc.

The variables available to your message may change based on the type of workflow, message, action, that you reference. While many variables are available when you preview a message, some, like deliveries only populate at send time.

editoralwaysDescribes the type of editor used to create an action. One of bee (email), html (email), json (custom push payload), wysiwyg (email, push notification, in-app, SMS, WhatsApp). For Create or update person actions, this value is blank.
action.idattribute updatesDescribes the ID of an action in a workflow.
action.nameattribute updatesDescribes the name of an action in a workflow.
action.typeattribute updatesBecause actions are always attribute updates, this value is _always_ attribute_update_action.
action.subjectattribute updatesThe attribute changed as a result of the action.
campaign.idalwaysThe identifier for the campaign, newsletter, broadcast, etc. "Campaign" in this context represents any workflow.
campaign.namealwaysThe name of a campaign.
campaign.typealwaysThe type of campaign/workflow. Can be one of behavioral (segment-triggered campaign), date , form , newsletter , transactional (event-triggered campaign), transactional_message (a transactional message), triggered_broadcast .
delivery.iddeliveries (at send time)The specific instance of a message sent to a person. We populate this value at send time; if you reference this value in any kind of preview, the value will be empty (because a preview does not generate a delivery).
layout.idemails where editor: "wysiwyg" or editor: "html"The saved layout used to create the message (if any).
layout.nameemails where editor: "wysiwyg" or editor: "html"The identifier for a campaign.
message.nameMessage actions, including newsletters and transactional messagesThe name of a message action that you set in the workflow.
message.idMessage actions, including newsletters and transactional messagesThe identifier for a message, set by
message.typeMessage actions, including newsletters and transactional messagesThe type of message action, one of email_action , push_action , slack_action , twilio_action , urban_airship_action , webhook_action .
message.journey_idMessage actions, including newsletters and transactional messagesThe identifier for the workflow path that the message action belongs to.
message.send_to_unsubsMessage actions, including newsletters and transactional messagesIf true, the message action is sent to unsubscribed people.

Filters and tags

Filters and tags make up the foundations of Liquid, and there are a number of them that you can use. In the first-name example, if you wanted to make sure it was capitalized, add a capitalize filter to the tag:

{{ customer.first_name | capitalize }}

If the field was full_name and you wanted to include only the first word/name, you could use:

{{ customer.full_name | split: " " | first }}

Check out the other filters and tags (and how to write them) in our complete Liquid documentation.

More examples: what else can you do?

 Use the Add Liquid option in the drag-and-drop email editor

If you use our drag-and-drop email editor to add user data, and you have code that involves logical or comparison operators (&, >, or <), use the “Add Liquid” option in the text dropdown, rather than typing liquid manually.

Countdown to an event

If your customers subscribe to an event—a webinar, they buy tickets to a movie or concert, etc—you can include a countdown to an event or specific date and time that your audience is interested in!

{% countdown point:64 font:roboto weight:light fg:000000 bg:f2f6f9 time:"2022-07-04 12:00:00 (GMT)" locale:en looping:true resolution:S frames:2 %}
countdown timer result
countdown timer result

Countdown timers take several parameters. Your timer must include the font size, the foreground (font) color, the background color, and the time you want to count down to.

pointintegerThe font size for the timer
timeISO 8601 timestampThe date and time you want to countdown to in the format YYYY-MM-DD hh:mm:ss (TZ). Remember to close the time in quotes, as the value includes a space.
fghex colorThe foreground (font) hexidecimal color
bghex colorThe background hexidecimal color
fontstringinter, robotoThe font family for your timer
weightstringnormalThe font weight, takes normal CSS font-weight values.
localelanguage codeenThe language you want to display: en (English), ru (Russian), jp (Japanese), zh (Chinese), pt (Portugese), es (Spanish)
loopingbooleanfalseDetermines whether the countdown timer should restart after it finishes
resolutionone of S, M, H, DSDetermines how often the timer counts down—by the second, minute, hour, or day.
framesinteger1Number of seconds you want to show, based on the resolution, where seconds: 60, minutes: 2, hours: 1, days: 1

Math operations with attributes

AttributesA key-value pair that you associate with a person—like their name, the date they were created in your workspace, etc. Use attributes to target people and personalize messages. are stored as strings—even if the attribute value is a number or an integer. When you want to use a number/integer attribute in a math operation, or evaluate it against another number, you need to convert the attribute to a number/integer to ensure that your liquid statements evaluate properly. You can do this using plus to add zero to the attribute.

{% assign my_attribute = customer.my_attribute | plus: 0 %}
{% if my_attribute > 0 %}
  Your attribute is greater than 0!
{% else %}
  Oh no, your attribute is 0 or negative.
{% endif %}

You can include attributes within links as well, in order to send your users to a custom page.


<a href="{{customer.ATTRIBUTE}}">

Displaying a timestamp as a regular date

Let’s say you have a customer attribute called expiration (for a trial, maybe) that you store as a timestamp. If you wanted to display that expiration date in messages as a human-readable date, you can do so with liquid. There are a few different date filters you can use with this, but here we’re just going to show you month name, day, and year.


If you had a customer attribute called expiration with a timestamp value of 1596153600, you can do the following:

{{customer.expiration| date: "%B %-d, %Y"}}

The result in your message would be July 31, 2020.

The spaces, commas, etc between the date filters are included in the output. So if you want 31/07/2020 you’d do %d/%m/%Y.

For the current date, you can use:

{{ 'now' | date: "%B %-d, %Y" }}

Displaying how many days left in a trial

{% assign current_date = 'now' | date: '%s' %}
{% assign future_date = customer.trial_end %}
{{ future_date | minus: current_date | divided_by: 86400 }}


  1. You can get the current epoch time with 'now' | date: "%s". %s is a formatting option.
  2. The customer.trial_end date is in epoch time.
  3. Since epoch time is in seconds, we’re dividing by 86400 (number of seconds in a day) to get the number of days. Keep in mind that this is integer division so it’ll be rounded down.

Compare two user or event attributes

While it’s not possible to compare attributes when you create segments or when you set up an event filter for your campaign, you can use liquid code inside your campaign’s content to achieve this purpose. The following example checks for equality:

{% if customer.attribute_1 == customer.attribute_2 %} 
	Hello awesome person! 
{% endif %}

But you can also use operators, such as >, <, and so on:

{% if customer.lifetime_value > 100 %} 
	Thanks for being a loyal customer! 
{% endif %}

Emails: Using a customer name in the ‘To’ field

This is done by using the following Liquid in your email’s ‘To’ field:

{{}} <{{}}>

Localizing date

If you want to display the current date formatted like: 06:54 AM Février 21, 2017 you can use this code replacing the months with the proper names for your desired lanuage:

{{'now' | date: "%H:%M %p %B %d, %Y" | replace: "January","Janvier" | replace: "February","Février" | replace: "March","Mars" | replace: "April","Avril" | replace: "May","Mai" | replace: "June","Juin" | replace: "July","Juillet" | replace: "August","Aout" | replace: "September","Septembre" | replace: "October","Octobre" | replace: "November","Novembre" | replace: "December","Décembre"}}

If you want to display the month in your customers’ language you can do this:

{{ event.invoice_date | date: "%-d" }}
{% case m %}
{% when '1' %}Janvier
{% when '2' %}Février
{% when '3' %}Mаrs
{% when '4' %}Avril
{% when '5' %}Mаi
{% when '6' %}Juin
{% when '7' %}Juillet
{% when '8' %}Août
{% when '9' %}Septembre
{% when '10' %}Octobre
{% when '11' %}Novembre
{% when '12' %}Décembre
{% endcase %}
{{ event.invoice_date | date: "%Y" }}

Show a different message based on day of week

{% assign day = 'now' | date: '%A' %}
{% if day == 'Friday' %}
Have a great weekend!
{% else %}
{% endif %}

Using data containing whitespace

We recommend adding data to without spaces. But if you do (for example, if you send us an attribute called current city), here’s how you’d refer to it:

{{ customer["current city"] }}

Filtering out default data or specific data

{% if customer.first_name contains 'Visitor' %}
	{% else %}{{ customer.first_name | capitalize }}
{% endif %}


Drag-and-drop editor users: If you’re writing more advanced Liquid including logical or comparison operators (&, >, or <, for example), use our Add Liquid dropdown option!

Looping through attributes

For this example, imagine each person has in their profile a list of friends, and you want to include this list in a message. Here’s an example of what the data you send to might look like in JavaScript:

  id:               "1",
  friends:   [ "Elaine", "George", "Kramer"]

Say the user with an id of 1 is “Jerry”. When you’re composing messages for Jerry, you can display his friend list using a Liquid for loop:

{% for person in customer.friends %}
  {{ person }}<br/>
{% endfor %}

And that’s it! That’ll display:

Elaine George Kramer

Looping through event data

Let’s go back to our event data example above, where a user bought some socks. Instead of making just one purchase (socks), let’s say they bought multiple items (socks, toothpaste, and dental floss), and you want to list them all in a particular message. If you sent us data like this (this example’s in Ruby):

customerio.track ( user_id, "purchase",
 :items => [
    {:name => "socks", :price => "23.45"},
    {:name => "toothpaste", :price => "3"},
    {:name => "dental floss", :price => "2.97"}

You can access that data to output a list by looping through it. This is how you’d do that:

{% for item in event.items %}
  {{ }} - {{ item.price }} <br/>
{% endfor %}

This will loop through your data and output the items that were passed in with the purchase event.

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