Sails.js structure looks nice and clean to me, so I use MVC style structure for my express projects, similar to sails.js.
project_root
|
|_ _ app
|_ _ |_ _ controllers
|_ _ |_ _ |_ _ UserController.js
|_ _ |_ _ middlewares
|_ _ |_ _ |_ _ error.js
|_ _ |_ _ |_ _ logger.js
|_ _ |_ _ models
|_ _ |_ _ |_ _ User.js
|_ _ |_ _ services
|_ _ |_ _ |_ _ DatabaseService.js
|
|_ _ config
|_ _ |_ _ constants.js
|_ _ |_ _ index.js
|_ _ |_ _ routes.js
|
|_ _ public
|_ _ |_ _ css
|_ _ |_ _ images
|_ _ |_ _ js
|
|_ _ views
|_ _ |_ _ user
|_ _ |_ _ |_ _ index.ejs
App folder - contains overall login for application.
Config folder - contains app configurations, constants, routes.
Public folder - contains styles, images, scripts etc.
Views folder - contains views for each model (if any)
Boilerplate project could be found here,
https://github.com/abdulmoiz251/node-express-rest-api-boilerplate