Retrieve all your active custom field keys, with optional filtering by entity type (customer, contract, product, etc.). Use this endpoint to discover what custom field keys are available before setting values on entities or to audit your custom field configuration across different entity types.
Bearer authentication header of the form Bearer <token>, where <token> is your auth token.
Cursor that indicates where the next page of results should start.
Optional list of entity types to return keys for
alert, billable_metric, charge, commit, contract_credit, contract_product, contract, customer, discount, invoice, product, rate_card, scheduled_charge, subscription