Prestozon works for all Amazon marketplaces available through the Amazon Ads API which includes: North America (Canada, Mexico and the US), Europe (France, Italy, Germany, Spain and the UK) as well as Japan, India, Australia and UAE. Unfortunately, China and the Netherlands are not currently supported through the Amazon Ads API.
Your accounts in other markets will be separated so that you get a dashboard for each profile (ex: US, Canada, and Europe). You can toggle easily between them using the drop down selector in the upper right corner.
