Standard Notes is a note-taking app with sync across devices. It supports Markdown, rich text, code snippets, lists, tasks and secure file storage, and always keeps an offline copy. According to Standard Notes, data is end-to-end encrypted so that only the user holds the keys (zero-knowledge). The source code is public on GitHub and, according to the company, independently audited. The service is delivered as an app with cloud sync and backups.
Since 10 April 2024, Standard Notes has been part of Proton, a Swiss company. Proton has stated that Standard Notes remains an open-source project and a separate product. Ownership therefore sits in Switzerland, which is outside the EU but a member of EFTA. Standard Notes' website does not state in which country synced data is stored. Because the content is end-to-end encrypted, a European organisation should mainly check which metadata the service processes and where it is held.