Hello,

I would like to be able to create custom fields and custom buttons through API. Though both of these are not included in the official API documentation, I found endpoints that work with both. (by adding custom fields in my browser and checking the request in the network tab)

It is possible to GET and POST custom fields through endpoint: https://books.zoho.com/api/v3/settings/fields

using the "Authorization" : "Zoho-oauthtoken {token}" header I can get and post what I need.

For the endpoint: https://books.zoho.com/api/v3/settings/custombuttons I can only do successful GET requests and query the currently existing custom buttons.

However, when I try to make a POST request, no matter what I do, I get an error:

I think it has something to do with authentication/cookies. But then again, the same strategy works for GET&POST on customfields and GET on custombuttons

Anybody with some advice?