I have built a lightweight, note taking application that focuses on quick note taking, and fully keyboard based usage. Notes are all one liner, and it supports minimum Markdown, you can manage tasks, reminders, do inline calculations, unlimited undo/redo. You can organize notes by project and categories.

https://mtarin.com/projects/nift/

Core point is simplicity, and frictionless note taking, and high performance, my dev version, can work with 12k notes without any issues.

Data is stored as text file.

Demo version is also available

I am looking for feedback, and wondering what would make people actually interested to buying this.

It's completely hand written, no AI assisted code.