> ## Documentation Index > Fetch the complete documentation index at: https://docs.cognite.com/llms.txt > Use this file to discover all available pages before exploring further. # Set up the SAP writeback service > Configure the SAP writeback service to create and update records in SAP S/4HANA from Cognite Data Fusion (CDF). To send requests to your SAP S/4HANA instance, set up the SAP host destination. An SAP instance is a configuration for an external SAP S/4HANA destination system. The instance resource contains all the information this API service needs to connect to the SAP S/4HANA destination. Send a **POST request** to `https://{cluster}.cognitedata.com/api/v1/projects/{project}/writeback/sap/instances` to create an SAP instance destination. See [API documentation](/api-reference/concepts/20230101/sap-instances) for more information. The SAP writeback service provides schema mapping functionality to map a CDF resource data schema to an SAP entity schema. The mapping must be defined using the Cognite extractor [mapping language](/cdf/integration/guides/extraction/hosted_extractors/kuiper_concepts). If you set a mapping, the SAP writeback service will apply the mapping expression before sending the request to the SAP destination. The example below contains an expression mapping the Cognite InField observation schema to the SAP maintenance notification schema: ``` { "NotificationText": substring(input.description,0,40), "MaintPriority": case(input.priority,"Very High","1","Medium","2","Low","3"), "NotificationType": input.type, "MaintNotifLongTextForEdit":concat(input.description,input.troubleshooting), } ``` Write the mapping expressions to fulfill your business needs regarding field or value mapping between Cognite Data Fusion and SAP entities. To save your mapping, send a **POST request** to `https://{cluster}.cognitedata.com/api/v1/projects/{project}/writeback/sap/mappings`. See [API documentation](/api-reference/concepts/20230101/sap-schema-mappings) for more information. In the SAP writeback service, an SAP **endpoint** is a configuration to an SAP S/4HANA OData endpoint (and its related OData entity). The API will send writeback requests to this endpoint. It defines which SAP instance destination and schema mapping should be used when processing a writeback request. Use the SAP **endpoint** as a reference to send requests to your SAP destination. To set the SAP **endpoint**, send a **POST request** to `https://{cluster}.cognitedata.com/api/v1/projects/{project}/writeback/sap/endpoints`. See [API documentation](/api-reference/concepts/20230101/sap-endpoints) for more information. The SAP writeback service provides an endpoint that checks if the connectivity between CDF and the configured SAP **endpoint** destination is successful. Send a **POST request** to `https://{cluster}.cognitedata.com/api/v1/projects/{project}/writeback/sap/endpoints/verify`. See [API documentation](/api-reference/concepts/20230101/sap-endpoints) for more information. For a successful connection, the response from the SAP writeback `/verify` endpoint looks like: ```json theme={"languages":{"custom":["/_languages/kuiper.json","../_languages/kuiper.json"]}} { "status": "success" } ``` Once you're done with the setup, send requests to your SAP destination. The SAP writeback service sends all requests to SAP asynchronously. Once you send a request through the service, you'll get a `requestId`. You can use the `requestId` to track the `status` of the request once it is completed. Send a **POST request** to `https://{cluster}.cognitedata.com/api/v1/projects/{project}/writeback/sap/requests` with the payload to be sent to SAP. See [API documentation](/api-reference/concepts/20230101/writeback-requests) for more information. This example shows a SAP writeback request to create a SAP maintenance notification. ```json theme={"languages":{"custom":["/_languages/kuiper.json","../_languages/kuiper.json"]}} { "items": [ { "endpointId": "test-notification", "request": [ { "payload": { "MaintNotifLongTextForEdit": "test description", "MaintPriority": "3", "NotificationText": "Test", "NotificationType": "M2" } } ] } ] } ``` Response: ```json theme={"languages":{"custom":["/_languages/kuiper.json","../_languages/kuiper.json"]}} { "items": [ { "createdTime": 1724416805132, "lastUpdatedTime": 1724416805132, "requestId": "0a0a0-1b1b-2c2c-3d3d-4e4e4e", "status": "pending", "request": [ { "payload": { "MaintPriority": "3", "NotificationText": "Test", "NotificationType": "M2", "MaintNotifLongTextForEdit": "test description" } } ] } ] } ``` To check the request status, send a **POST request** to `https://{cluster}.cognitedata.com/api/v1/projects/{project}/writeback/sap/requests/byids` with the related `requestId`. See [API documentation](/api-reference/concepts/20230101/writeback-requests) for more information. Request: ```json theme={"languages":{"custom":["/_languages/kuiper.json","../_languages/kuiper.json"]}} { "items":[ { "requestId":"0a0a0-1b1b-2c2c-3d3d-4e4e4e" } ] } ``` Response: ```json theme={"languages":{"custom":["/_languages/kuiper.json","../_languages/kuiper.json"]}} { "items": [ { "createdTime": 1724416805132, "lastUpdatedTime": 1724416806161, "requestId": "0a0a0-1b1b-2c2c-3d3d-4e4e4e", "status": "done", "request": [ { "sapObjectId": "10129745", "payload": { "MaintPriority": "3", "NotificationText": "Test", "NotificationType": "M2", "MaintNotifLongTextForEdit": "test description" } } ] } ] } ``` The writeback request is completed when the request status is set to `done`. The response parameter `sapObjectId` contains the object ID of the record created in the SAP destination. Sign in to your SAP server and go to transaction code `IW23` to check the **maintenance notification** created by the writeback request. Input the `sapObjectId` value available in the writeback response. SAP maintenance notification showing created record The writeback service can send update requests to SAP. The request is similar to the `create` request in step 5. However, the object ID of the SAP record must be available in the request payload. ```json theme={"languages":{"custom":["/_languages/kuiper.json","../_languages/kuiper.json"]}} { "items": [ { "endpointId": "test-notification", "request": [ { "payload": { "MaintenanceNotification":"10129745", //Object ID of the SAP Maintenance Notification you want to update "MaintNotifLongTextForEdit": "Updated description", } } ] } ] } ```