Message Preparation

Required
Reusable Content Block

The following Liquid code snippet is used in your email to call the JQRDContent content block to fetch dynamically optimised language from Jacquard.

1. Paste the code snippet into the part of the email you're optimising

New variable names
January 2026 Variable names in this code snippet have changed. When using make sure to update your Connected Content block.

{% assign JQRDExperimentId = 'experimentID' %}
{{content_blocks.${JQRDContent}}}{% comment %}{% endcomment %}
{% if {{variants.variant_text}} == blank or {{variants.variant_text}} == null %}
PASTE YOUR HUMAN CONTROL HERE
{% else %}
{{variants.variant_text}}
{% endif %}

If your Jacquard language variants contain any personalisation tags, please expand the section below for further instructions.

Add personalisation tags to the language code snippet (optional)

Personalisation includes anything from first name to product. It is any field Braze will need to process to plug in information unique to a user.

You'll need to add your personalisation tags them to your subject line code snippet in between the {% comment %} and {% endcomment %} tag.

If you don't include the personalisation tags within the comment tags, Braze won't process them properly and they'll be rendered as literal text within your subject line. This would result in something like Hi, {{$first_name}} showing up in a subscriber's inbox.

Our example below shows how a code snippet might be configured with Braze's default first name personalisation field:

{% assign JQRDExperimentId = '69287a23e29261ae299e24a9' %}{{content_blocks.${JQRDContent}}}{% comment %} {{${first_name}}} {% endcomment %}
{% if {{variants.variant_text}} == blank or {{variants.variant_text}} == null %}
🛠️ There's so much to explore out there
{% else %}
{{variants.variant_text}}
{% endif %}

Note the placement of the {{${first_name}}} tag between the comment tags.

If you require multiple personalisation tags, you can simply add them between the {% comment %} and {% endcomment %} tag with a space between them, as in:

{% comment %} {{${first_name}}} {{${last_name}}} {% endcomment %}

If your personalisation tag uses Liquid Filters to modify the output, then these filters need to be assigned along with the tag to a new variable. It's this variable that would then appear in your Jacquard language.
For example, if you want to capitalise the first_name field with {{${first_name} | capitalize}}, then you must first assign this to a new variable before calling the Jacquard Content Block:
{% assign capitalizedFirstName = {{${first_name} | capitalize}} %}
{% assign JQRDExperimentId = '69287a23e29261ae299e24a9' %}{{content_blocks.${JQRDContent}}}{% comment %} {{capitalizedFirstName}} {% endcomment %}
{% if {{variants.variant_text}} == blank or {{variants.variant_text}} == null %}
🛠️ There's so much to explore out there
{% else %}
{{variants.variant_text}}
{% endif %}
Note how the assign capitalizedFirstName appears before the assign JQRDExperimentId and also how the newly created variable, {{capitalizedFirstName}}, now appears between the comment tags instead of the default personalisation tag.

In this example, we're optimising a subject line and so have pasted the code snippet into the Subject field of our Braze email campaign.

2. Replace the experimentID placeholder with your experiment ID

Each Jacquard experiment has a unique experiment ID. You'll need to paste your experiment's unique ID over the <experimentID> placeholder in the code snippet.

If you need help locating your experiment ID, see our ID documentation.

When pasting your experiment ID, ensure you leave the apostrophes surrounding the placeholder intact, but remove the angle brackets, as in the example below:

3. Replace the fallback placeholder with your human control language

The code snippet has fallback logic in place in the event Braze encounters problems processing the snippet.

You'll need to replace the PASTE YOUR HUMAN CONTROL HERE placeholder text with your actual human control language from your Jacquard experiment:

4. Test your email

Once you've added your code snippets properly to Braze and activated your experiment in Jacquard, you should be able to preview the email and see your subject lines populating dynamically.

In addition to previews, we always recommend as a best practice to do a live deployment to a small, internal test list to ensure everything will function correctly in a live send.
CEPs often render previews differently than live sends, so it is important to test both.

After you've set all of this up for the first time, save your code snippets somewhere safe so you can simply reuse them in the future by swapping out the experiment ID and human control language.

Once you've verified your code snippets and personalisation tags (if used) are functioning properly, you've completed your minimum email setup.

Continue along the article path for important instructions for deploying your experiment.