When linking a lead to a company, externalCompanyId is used. This means when adding a contact from CRM (via the web API), I can specify our CRM's unique identifier rather than having to find the Marketo's generated Company Id first.
Our team has created a custom Object, but cannot link to Company based on externalCompanyId, only Id. This means for each custom object, I will have to get the Id for the Company first before creating/updating the custom object, rather than specifying the externalCompanyId and allowing Marketo to handle the lookup, as is the case with leads.
Marketo's UI doesn't allow me to link based on externalCompanyId, so I though it may be possible via the API. However, the API also throws an error when trying to link with this field, although Marketo is describing it in the docs as an arbitrary string field.
Does anyone have a suggestion on how to tackle this issue? Your help would be much appreciated.
Sorry, we have only linked on Lead, not on Company. I've found this but likely you have already seen it: https://docs.marketo.com/display/public/DOCS/Understanding+Marketo+Custom+Objects#UnderstandingMarke....
I hope this helps somewhat! My experience with Leads was that Marketo only let us link with certain fields as well (Salesforce ID I think in our case).