My question is how to have sync between sharepoint onpremise and online. That will fetch data from onpremise and show it in sp online and any updates in the online list will again reflect in onpremise. I have seen some references already like BCS, Azure connection and Data gateway. There is no demo or explaination on how to achieve. I look for solution using power automate or spfx. Can anyone help with your suggestions.
You can use tools from market such ShareGate, AvePoint, Metalogix. Another one it's Veeam Backup & Replication have module/product SharePoint Backup and Replication for OnPrem and O365. I think you can prepare backup onPrem (by schedule) and replicate to SharePoint Online.
If you looking for free tools you can check SPMT from Microsoft (https://docs.microsoft.com/en-US/sharepointmigration/introducing-the-sharepoint-migration-tool)
Synchronizing SharePoint on-premises and online environments can be achieved using Power Automate or SharePoint Framework with a few different approaches.
Power Automate offers a user-friendly way to establish synchronization. You can create a flow that initiates the sync process using triggers like "When a new item is created." The flow can be set up to retrieve data from the on-premises SharePoint list using the "Get items" action and create new items in the online SharePoint list with the "Create item" action. Additional actions like email notifications or updates to other systems can also be integrated into the flow. This method provides a streamlined and automated approach.
On the other hand, SPFx provides a more customized solution. You can develop a custom web part that interfaces with both environments using the SharePoint REST API. The web part retrieves data from the on-premises list and creates new items in the online list. Once deployed in SharePoint online, the web part facilitates automatic synchronization from the on-premises to the online environment. SPFx is ideal for situations requiring more flexibility and tailored functionality.
The choice between Power Automate and SPFx depends on your specific requirements. For straightforward and efficient synchronization, Power Automate is recommended. For scenarios demanding greater adaptability and customization, SPFx is the preferred route. Additionally, consider using a hybrid identity solution to enable unified sign-ins across both environments, data gateways to connect Power Automate with SharePoint on-premises, or explore third-party tools for additional synchronization options. These strategies will help you seamlessly manage data across SharePoint on-premises and online platforms.