Magento 2 Shipping and Payment Method per Customer Group supports both types of API: REST and GraphQL. You can check the details in the below links.
REST API
Please find in this list the REST APIs that Magento 2 Shipping and Payment Method per Customer Group extension supports.
Magento 2 Shipping and Payment Method per Customer Group REST API Support
GraphQL API
This list presents all GraphQL APIs supported by Magento 2 Shipping and Method per Customer Group extension.
Magento 2 Shipping and Payment Method per Customer Group GraphQL API Support
Notes
- When getting the list of payment & shipping methods and checking the allowed methods, the module does not check the config status (enable or disable). Therefore, when using the APIs you need to check the module config as well.
- When assigning the shipping or payment methods to customer groups, separate the chosen methods with a comma, e.g. group_ids: "0,1,2".
- Type is either "payment" or "shipping".