Hey there,
Incremental load and write-back extensions serve different purposes in Qlik Sense.
Incremental load is a technique used to load only new or changed data from a data source into a Qlik Sense app. This can improve the performance of data reloads by reducing the amount of data that needs to be loaded. Incremental load is typically used when loading large amounts of data from a data source that changes frequently.
Write-back extensions, on the other hand, allow users to enter or update data directly within a Qlik Sense app. This data is then saved to an external data source, such as a database or a file. Write-back extensions are typically used to support planning, forecasting, and other scenarios where users need to enter or update data within the app.
The main difference between incremental load and write-back extensions is the direction of the data flow. Incremental load is used to load data from an external data source into a Qlik Sense app, while write-back extensions are used to save data from a Qlik Sense app to an external data source.
Write-back extensions can be used independently of incremental load. The data source for a write-back extension is determined by the extension itself and can be different from the data sources used for loading data into the app.
Please do refer to these links for more information
Loading new and updated records with incremental load | Qlik Sense on Windows Help
Writeback extension - Qlik Community - 2030145
