HubSpot appears to have a variety of default contact properties built into the system. Using /properties/v1/contacts/properties I'm only getting the properties that were set on a test contact (firstname, phone, createdate, email, lastname). I'd like to see ALL available default properties that can be used on contacts, not just those that have been used previously in test cases.
I know there are additional properties available in the system such as "job title", "company name", etc. How do I get a list of those properties?
The contact properties API should return all property definitions, not just the ones where a contact has a value. It sounds like you're both testing this in your developer portal, which might explain the strange behavior. You should use test portals instead; you can create any number of test portals from the 'Testing' tab of your developer portal. Test portals are fully functional Marketing Enterprise trials, so you can test any of the HubSpot APIs:
In the developer portal, there is no "contacts" area. That help document was not useful.
I've given up on using my developer account and instead am doing development work with the production account which does have full access. I recommend setting up development accounts to be more fully-functional in the future so developers can write code to test everything before moving on to production accounts.