Paperwork
Paperwork aims to be an open-source, self-hosted alternative to services like Evernote, Microsoft OneNote or Google Keep.
For the back-end part a MySQL database stores everything. With such common requirements (Linux, Apache, MySQL, PHP), Paperwork will be able to run not only on dedicated servers, but also on small to mid-size NAS devices (Synology ®, QNAP ®, etc.).