I recently was trying to send an email to a list containing different contacts but some did not have the First Name field filled in and was blank. So I did some google searches for a solution and came across these two posts: HubSpot forum topic and HubSpot forum topic 2.
I tried the code shared in the posts and they must be outdated because they did not work for me. I wrote a cleaner version below that checks if the first name field has content and if so display the name. If the field is blank use some default text.
The Code
{% if contact.firstname %}Dear {{ contact.firstname }},{% else %}Dear Customer,{% endif %}
What the code does
“Dear First Name,” OR “Dear Customer,”