HubSpot HubL JSON Parsing: Fix 'fromjson' Errors in Emails

Hey there, ESHOPMAN readers! We often talk about leveraging HubSpot to its fullest, especially when it comes to creating dynamic and personalized experiences for your customers. Whether you're trying to create your own ecommerce website or just enhance your customer journey, getting your data to play nice across different HubSpot tools is key. Today, we're diving into a common developer headache that popped up recently in the HubSpot Community: parsing JSON strings from contact properties within HubL, specifically in email templates.

It's a fantastic goal – imagine storing a customer's recent activity, preferred routes, or even a mini-cart of abandoned items as a JSON string in a contact property, then dynamically displaying that information in a personalized email. Powerful stuff, right?

The HubSpot Community Dilemma: 'fromjson' Not Playing Nice

A community member recently posted about a challenge they were facing. They were trying to store a JSON string in a contact property (let's call it contact.rutas for this example, as they did) and then parse it using the fromjson filter in a HubSpot email component. Their goal was to iterate through an array within that JSON to display dynamic content like points of interest (POIs) with titles and descriptions.

They shared their code, which looked something like this:

{% set raw_rutas = contact.rutas %}

{% if raw_rutas and "{" in raw_rutas and "[" in raw_rutas %}
  {% set rutas = raw_rutas|fromjson %}

  {% for poi in rutas.pois %}
    {{ poi.title }}
    {{ poi.description }}
  {% endfor %}
{% endif %}

Or even a simpler attempt:

{% set raw_rutas = contact.rutas %}
{% set rutas = raw_rutas|fromjson %}

The problem? They kept hitting a wall with an error message: Invalid input for 'fromjson': input could not be converted to an object. This is a classic indicator that the fromjson filter, while powerful, is incredibly strict about the format of the string it's trying to parse.

The original poster had already checked HubSpot's documentation and other community threads, but couldn't get it to work. A community moderator chimed in, acknowledging the complexity and reaching out to other experts for their best practices, even linking to another related discussion.

Why 'fromjson' Can Be Tricky in HubSpot Emails

The 'Invalid input' error is almost always a tell-tale sign that the string you're feeding to fromjson isn't perfectly valid JSON. HubL's fromjson filter expects a pristine JSON string. Any deviation – an unescaped quote, a trailing comma, single quotes instead of double quotes for keys or values, or even extra whitespace or HTML tags – will cause it to fail.

This is especially common when the JSON string is generated externally (via API, webhook, or a custom integration) and then stored in a plain text contact property. Sometimes, the method of saving the data into HubSpot might introduce subtle formatting issues, or the original data itself wasn't perfectly compliant.

Solving the 'fromjson' Puzzle: Your Actionable Steps

Here’s how you can approach this challenge and ensure your JSON strings are parsed correctly for dynamic email content:

Validate Your JSON Source: Before it even hits HubSpot, ensure the JSON string you're generating is valid. Use an online JSON validator to check it.
Inspect the Raw Contact Property Value: The first step in debugging is to see exactly what HubL is receiving. Temporarily print the raw string in your email:
```
Raw JSON from contact property: {{ contact.rutas }}
```
This will often reveal hidden characters, incorrect escaping, or malformed JSON that you didn't expect.
Clean the String Before Parsing: Even if your source JSON is perfect, HubSpot contact properties can sometimes introduce subtle issues. Use HubL filters to clean it up. striptags removes any potential HTML, and trim removes leading/trailing whitespace.
Robust Conditional Parsing: Always check if the string exists and then attempt to parse, providing fallback content if it fails.

Example of a Robust HubL Implementation:

Here’s an improved version of the original poster’s code, incorporating these best practices:

{% set raw_js %}

{% comment %}
  First, ensure the string is clean and not empty.
  The 'fromjson' filter is very strict.
  Common issues: extra whitespace, HTML tags, or malformed JSON.
{% endcomment %}
{% if raw_json_string is string and raw_json_string|length > 0 %}
  {% set cleaned_js %}

  {% comment %}
    Attempt to parse. It's crucial the string is valid JSON.
    If it fails, 'rutas' will likely be undefined or cause an error.
    HubL doesn't have a try-catch, so we rely on post-parsing checks.
  {% endcomment %}
  {% set rutas = cleaned_json_string|fromjson %}

  {% comment %}
    Now, check if 'rutas' is an object/array and iterate.
    This check prevents errors if 'fromjson' failed silently or returned null/invalid.
  {% endcomment %}
  {% if rutas and rutas.pois is iterable %}
    Your Recent Activity Highlights:
    {% for poi in rutas.pois %}
      {{ poi.title }}
      {{ poi.description }}
    {% endfor %}
  {% else %}
    Oops! We couldn't parse your activity data. Debug string: {{ cleaned_json_string }}
  {% endif %}
{% else %}
  No personalized activity data found for you at the moment.
{% endif %}

This approach first cleans the string, then attempts to parse it, and finally checks if the parsing was successful and if the expected data structure (rutas.pois) exists and is iterable. This makes your email templates much more resilient to malformed data.

ESHOPMAN Team Comment

This community discussion highlights a fundamental challenge in leveraging CRM data for dynamic e-commerce experiences. While storing complex activity logs as JSON in a contact property isn't always the ideal long-term solution (custom objects are often better for structured, related data), it's a pragmatic workaround given certain HubSpot plan limitations. The key takeaway from our perspective is that data hygiene is paramount; the fromjson filter's strictness is a feature, not a bug, forcing developers to ensure their inputs are perfectly valid. For any business trying to create their own ecommerce website and integrate deeply with HubSpot, mastering these data handling nuances is crucial for truly personalized customer journeys.

By implementing these robust parsing techniques, you can unlock a world of personalized content in your HubSpot emails. Imagine sending targeted promotions based on past purchases, displaying recently viewed products, or even showing a dynamic progress bar for a loyalty program – all powered by clean, well-parsed JSON from your contact properties. This level of personalization is what truly sets successful online stores apart, transforming generic messages into highly relevant customer communications. Keep experimenting, keep learning, and keep making HubSpot work harder for your e-commerce business!