How to Integrate Solarwinds with Servicenow using API for fetching the devices and populating in CMDB(ServiceNow).
Licensing is maybe a hurdle, but if you own any of the Service Now ITOM features you might be able to leverage the Service Graph Connector for SolarWinds. Check with your service now account people. It will do the heavy lifting and gets regular updates. ServiceNow Store
If you are looking to build your own, I can say that I did that, and it felt like it needed constant care and feeding. You will likely use an import task which puts the data here: CMDB Data Ingestion API | ServiceNow Developers and pulls from the Orion rest API from a MID server on your network. You will pull it from the Orion REST API interface, take a look at these linksGitHub - solarwinds/OrionSDK: SDK for the SolarWinds Orion platform, including tools, documentation, and samples in PowerShell, C#, Go, Perl, and Java. Swagger UI (solarwinds.github.io)
https://docs.servicenow.com/en-US/bundle/sandiego-platform-administration/page/administer/exporting-data/task/t_ExportDirectlyFromTheURL.html
One way is to export it through a URL. This is how I have been grabbing CBDB Data for our Powershell scripts.