Common Shopify Liquid Mistakes

1. Forgetting to Escape Output

If a merchant types <script> into a standard text setting, and you output it directly, it could break your layout or cause security issues. Always use the escape filter for plain text.

<!-- Bad -->
<h2>{{ section.settings.title }}</h2>

<!-- Good -->
<h2>{{ section.settings.title | escape }}</h2>

2. Incorrect Loop Limits

Shopify enforces a strict 50-item limit on pagination. If you try to loop through collection.products without pagination, it will silently cap at 50.

{% paginate collection.products by 12 %}
  {% for product in collection.products %}
    ...
  {% endfor %}
  {{ paginate | default_pagination }}
{% endpaginate %}

3. Assigning Booleans as Strings

When checking conditions, remember that Liquid has true boolean values.

<!-- Bad -->
{% if product.available == 'true' %}

<!-- Good -->
{% if product.available %}

4. Using Javascript inside Liquid Loops

If you output a <script> tag inside a for loop, you will generate identical scripts multiple times, destroying performance. Always put scripts outside loops, and pass data via data-attributes instead.

5. Forgetting block.shopify_attributes

Without {{ block.shopify_attributes }} on block wrappers, the theme editor cannot highlight individual blocks—merchants think the section is "broken."

6. Using Deprecated img_url

Replace img_url with image_url and image_tag. Details in our Image Optimization Guide.