Need some web project ideas like management systems or other

I wanted to get some web project ideas to build. I had thought of an attendance management system which I would build using java framework like springMVC or struts and build a rest api for the same, which would get the result to the frontend.

The functionalties would include login/sign up for teachers and students, also a key feature would be the authorization to teachers to take attendance and give the teacher an update whenever a students attendance is low.

But the idea has already been taken by someone else and I can't implement it, So I really need some project ideas that are similar or are different.

I will work in a team of 4 (including me) so the team will be divided in frontend development and backend development.

The technologies that can be used in coding are Java and frameworks like struts, spring, Nodejs, Angularjs, Expressjs. The database technologies (NoSQL and SQL) which can be implemented are MySQL, Derby, Redis, MongoDB. Webservices or api building can also be used.

I wanted to ask for projects where the backend is api and frontend can be any web technology, so the api can be reused for an app service.If this is not possible, I would really appreciate any other ideas you guys will have.

I would really appreciate any help or opinion that is given.