# DirectBilling ## Retrieving a list of services - [GET /directbilling](https://docs.simpay.pl/en/apis/directbilling/directbillinggetservices.md) ## Retrieving service information - [GET /directbilling/{serviceId}](https://docs.simpay.pl/en/apis/directbilling/directbillingservice.md) ## Commission calculation - [GET /directbilling/{serviceId}/calculate](https://docs.simpay.pl/en/apis/directbilling/directbillingservicecalculate.md) ## Retrieving a list of transactions - [GET /directbilling/{serviceId}/transactions](https://docs.simpay.pl/en/apis/directbilling/directbillingtransactions.md) ## Generating a transaction - [POST /directbilling/{serviceId}/transactions](https://docs.simpay.pl/en/apis/directbilling/directbillingtransactioncreate.md) ## Retrieving transaction information - [GET /directbilling/{serviceId}/transactions/{transactionId}](https://docs.simpay.pl/en/apis/directbilling/directbillingtransaction.md) ## Receiving DirectBilling transaction information - [POST directbillingTransactionNotification](https://docs.simpay.pl/en/apis/directbilling/directbillingtransactionnotification.md): # Signature ## Calculating the signature when receiving a notification We generate the signature by combining all the parameters received (except for the signature) to the API in the order from the table above, separating them with a | separator and adding at the end the key available in the customer panel in the service. Hashing must be done using sha256. Example: dc261d4f-31ef-4728-bfd6-97bbe2a5ef0a|e14f8074|transaction_db_payed|11.07|13.67|5.00|https://www.simpay.pl/complete|https://www.simpay.pl/failure|test|123123123|1|key The notification is sent using the POST method and requires you to respond in the body with OK and Http Code 200