Payday is a cloud service from Iceland that combines invoicing, payroll, accounting and reporting for businesses. The vendor's site presents these functions as one online system for business operators. The operating company is Payday ehf., based in Kópavogur. The product is not presented as open source.
Payday ehf. is an Icelandic company, and Iceland is part of the European Economic Area. The site shows a Visma logo and links to the Visma Group, which suggests group membership, but it does not state who owns the company, so this is not confirmed here. The pages consulted do not say where data is hosted, and the privacy policy is only linked. For a European organisation, EEA membership brings the GDPR into scope, but the hosting location and any group ownership should be confirmed with the vendor before use.