Crelate API: authenticate with an API key and create or update a record

Steps

1. In Crelate, go to Settings > My Settings & Preferences to view/enable your personal API key (an org admin must first enable API access for non-admin users under Settings > Advanced Settings > User Roles).
2. Append the key as a query-string parameter on every request, e.g. https://app.crelate.com/api3/{resource}/{id}?api_key={key}.
3. To create or update a record, send the entity fields as JSON, supplying required attributes for that type (e.g. Company requires Name; Job requires Name; Note and Task require Body).
4. For lookup fields (suffixed _Id, e.g. AdditionalContact_Billing_Id), either pass the related record's Id to attach an existing record, or leave Id blank and supply FirstName/LastName to have Crelate create a new linked contact.
5. Send all dates in ISO 8601 UTC format (e.g. 2017-01-01T15:00:00Z); other formats or time zones can fail or produce unpredictable results.
6. Use the published Swagger definition (https://app.crelate.com/api3/swagger/v3/swagger.json) to confirm the exact field set and generate a typed client if needed.