How do I read and update an opportunity's custom field?

I am a really young beginner here to using anything related to an API.
I am desperate to figure out how to use json to read an opportunity’s custom field as well as update an opportunity’s custom field.

I am trying to build a custom Zapier connection to do this and I am not having any luck understanding how to do this at all.

From what I can tell there is not a way to do this with the REST API. Which is a bummer as I have a custom zap that can find an opportunity and then update it. But, there is not way to read or update any custom fields with the same method.

I have looked over the legacy XML API and this looks possible somehow but I have not idea how to do this. Any help would be VERY appreciated.

Regards,

Dillan

Just as you would with contacts, custom fields on the opportunity table can be written to the ‘Lead’ table by including a create/update field array with the custom fields preceded by an underscore. so include in your field mapping ‘_thisFieldName’=>‘this field value’

@Dillan_Archer The API Team is presently working on exposing custom fields for Opportunities through the REST API. I can’t offer a release date, but I would expect it sometime in the next couple weeks.

AWESOME! I am super excited to hear that!

I am really looking forward to that update.

Thank you for letting me know.