What is the difference between the MWS API and SP-API?

They are one and the same. The MWS API provided Seller Central Operational data and was deprecated in favor of the SP-API in July of 2022.

The SP-API provides all the data previously available through the MWS API, but also includes additional data sets such as Brand Analytics data, Vendor Retail Analytics data (Sales, Traffic, Forecast, and Inventory reports) and Seller Business Reports data (Detail Page Sales and Traffic Report by Child Item).

Amazon has expressed that the SP-API will continue to expand the available reports, and for the latest information, please contact us directly.