- IAP is not limited to the Odoo framework. You can develop a service provider module in any other platform or framework. Just make sure that it can handle JSON-RPC2 (https://www.jsonrpc.org/specification) requests.
- If you develop a service provider in any other platform, you will also need to manage a transaction manually by using IAP endpoints. You will need to authorize and capture credit by requesting IAP endpoints. You can get endpoint information at https://www.odoo.com/documentation/12.0/webservices/iap.html#json-rpc2-transaction-api.