Opensource Private Search is an open source search engine.

I don't have the backend hosted in any public place at the moment, you need to host it yourself

This is the normal frontend version you will use if you host the backend in your network for your own personal usage: https version

If you want to host the server locally and allow anyone else to access it without setup a full enviroment (buy domain, generate certficates, set https...), you can use this http version that will allow you to run the backend in local and share it using ngrok.