post https://api.ramp.com/developer/v1/accounting/field-options
You can upload up to 500 new field options for a given custom accounting field in an all-or-nothing fashion. If a field option within a batch is malformed or violates a database constraint, the entire batch containing that field option will be disregarded.
To have a successful upload, please sanitize the data and ensure the field options that you are trying to upload do not already exist on Ramp.
If a field option is already on Ramp but you want to update its attributes, please use the PATCH developer/v1/accounting/field-options/{id} endpoint instead.