Upon installation and with the last version of the API :
/home/******/Dev/********/.bundle/ruby/3.1.0/gems/easy_hubspot-1.0.0/lib/easy_hubspot/client.rb:39:in `parse_response': Invalid input JSON on line 1, column 12: Unrecognized token 'properties': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false') (EasyHubspot::HubspotApiError)
This works : EasyHubspot::Contact.create_contact({ properties: { email: '', firstname: '', lastname: '' , etc: ''}}.to_json)
The same applies to update (update_contact(@hubspot_id, { properties: properties }.to_json))
I got really mad trying to use the official gem, so it would be nice to have a maintained gem with a clean and friendly API like yours :)