We'd like to have Hubspot be able to read and write to our own custom application API and vice-versa. From what I'm seeing, HubSpot won't specifically trigger outside of webhooks (e.g., it seems there's some limited action by Webhooks that could trigger an external app's behavior).
An example of one thing would be to have our Products available when creating Deals pull directly from our internal applications product offerings. It seems the only way to do this is have the internal app "sync" (manage, create/delete/update HubSpot data via the Products API). There doesn't seem to be a way to make Products pull from a feed – but I wanted to reach out to confirm this.
Doing research for a client and the sales/support team simply sends me here – so I'm hoping someone who is better versed will answer!