We have a webhook with subscriptions on Company and Contact objects- but are not getting events notice when Contact Company association changes (Contact changes Company)
I see the contact property “associatedcompanyid” is referred to in several places but can’t seem to find it in the webhooks event subsciptions GUI web page.
No field matching “associatedcompanyid” that exists under contact event subscriptions.
Are there any examples of how to do this?
Ref :
Hey, @ERudrud 
You are not missing an option. It is not possible to fire a webhook for associations specifically. There is some additional discussion here, but no workarounds provided:
If you have a moment, adding this to the Ideas Community would be helpful. This allows you to share your use case with the Product team.
Thank you! — Jaycee
FYI I had a similar need.. created this idea for what its worth..
HubSpot Community - Need webhook fired on association change - HubSpot Community
Thank you so much for sharing that Idea link, @SPhadke 
I added my upvote — Jaycee
I think `Number of associated contacts` company property is the solution here. It always updates it’s value when a contact associated to a company. We can use it for trigger a workflow or trigger an event subscription.
Original answer: https://community.hubspot.com/t5/APIs-Integrations/How-can-I-listen-on-association-change-via-webhook/m-p/456836#M44920