In the EU: the database in Ireland (AWS eu-west-1) and the API in Frankfurt (Germany) and Paris (France). The data processing agreement lists every sub-processor with its location and transfer safeguard.
General information, not legal advice. National laws can add to the EU texts quoted here, for example deadlines, forms or reporting channels: check your own country's rules.
This answer also appears, with more context, here: EU data residency
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