Introduction:
If you want to use HotJar tracking this guide will show you what you need to do.
Note that we have users report that HotJar wont work with LeadsHook when using GTM. So you need to manually install the tracking code into your global or DT level script section.
Step-by-Step Instructions:
Step 1: Log into your HotJar account
Step 2: Go to the Sites list
Step 3: Click on the Tracking Code button for the Site you want to track.

Step 4: Click on Copy to Clipboard.
Step 5: Log into Leadshook & paste the tracking code into the <head> section of a DT level script.
EMBED UPDATE
We added the ability to add html attribute to allow tools like hotjar to work without hacking the code.
https://help.hotjar.com/hc/en-us/articles/115011624347-Can-I-track-iframes-inside-Recordings-

UPDATE: 7 Nov 2020
We received the followijg advice from someone who has been able to make Hotjar work….
“I am adding “data-hj-allow-iframe” (WITHOUT # at the end) as Append Iframe Attributes to Embedded code. I also noticed that blank white space appears when there is a GTM code on the Landing Page as well (in addition to one in Decision Tree). That’s why I don’t install GTM on Landin Page itself. Only the Decision Tree.”