Standard Notes is a simple, secure, open-source note-taking application. Notes can be synchronized across devices using end-to-end industry standard AES-256 encryption. In addition to the public sync servers, more technical users may also opt to run their own. Instructions are provided for setting up such a server on Amazon EC2, Docker, or Heroku. Standard Notes provides a backup feature that allows users to download the entire content of their account. Tools are available to convert these backup files into folders of plain-text documents so that users can easily migrate to another system. Standard Notes is available on the desktop for Windows, macOS, and Linux. Mobile versions are available for iOS and Android. A web interface is also available that works in any modern browser. Source code for all the versions of Standard Notes is available on GitHub.