I am currently building a really complex application using Mobx, it’s great! Because of how it works you can do things that are impossible with redux - as the state would take too long to update with redux. I’m also using mobx-state-tree which is like the love child of mobx and redux. Amazing project as well, should be used if you want to have explicit model validation and immutability. I used it to build a history feature - that would have been almost impossible with vanilla mobx.