Yotpo (Yotpo Ltd., New York, USA) is widely used for customer reviews. These Shopify apps come from providers based in Europe. What I could document about privacy and hosting is on each detail page.
Copenhagen, Denmark
Collect and manage Trustpilot reviews and show them in the store through app blocks.
For customer reviews, the directory lists this app from European providers: Trustpilot. I checked each provider's location against a source.
No. A European headquarters does not mean all data stays in the EU. Each detail page says what I could document about the DPA, hosting and subprocessors, and what is still open.
Yotpo is made by Yotpo Ltd., New York, USA.