Web development – Building a drag & drop web application + programming.

I'm looking for a platform that gives me the ease of use of drag-and-drop UI elements and the flexibility to write my own code.

The ideal would be a system that allows me to drag a button to the screen and then write backend functionality in some language (php?).

Some options:

  1. Wix– after being a long time user, this is by far the most advanced drag-and-drop platform, But they try to keep their system a closed garden. You can write code only using your own API and database. It is not free to access your own DB / do what you want.

  2. Other platforms (Space squared, Shopify, etc.) give you a ready user interface, and almost no flexibility to write the back-end code freely.

Is there any serious tool today, which allows me to skip the boring part of the programmatic design of the user interface, and simply drag elements to create a good user interface, and at the same time just write the code behind each interface element of user on my own?