You can integrate Provide ECO to SAP in ABAP! Check out the following abapGit repo below for more details:
ABAP backend : https://github.com/fleischr/provide-eco-sflight-demo-abap SAP Fiori frontend : https://github.com/fleischr/provide-eco-sflight-demo-ui5
For cloud-native integration on SAP Business Technology Platform (BTP) - see the javascript example!