Simplenote uses Simperium to store and sync notes across multiple app platforms. The Simperium libraries handle all the networking so developers can focus on building a great user experience.
Contribute to Simplenote
All of the Simplenote apps are open source and ready for your contributions! You can find the source on GitHub:
Electron (Windows, Linux, and the web app): https://github.com/automattic/simplenote-electron
The README files on each of those repositories have all of the instructions you need to get started!
Third Party Applications
We are not supporting additional third-party Simplenote applications at this time. This could change though, so please stay tuned!
Legacy Simplenote API
Some older applications may still be using the legacy Simplenote API at https://simple-note.appspot.com. Note that this API has been deprecated and will no longer function after October 1, 2018.