# The Sails app lifecycle The Sails core has been iterated upon several times to make it easier to maintain and extend. As a result, it has a very particular loading order, which its hooks depend on heavily. This process is summarized below. ### (1) Load configuration "overrides" Gather the set of configuration values passed in on the command line, in environment variables, and in programmatic configuration (i.e. options passed to [`sails.load`](https://sailsjs.com/documentation/reference/application/sails-load) or [`sails.lift`](https://sailsjs.com/documentation/reference/application/sails-lift)). When an app is started via the command-line interface (by typing `sails lift` or `sails console`), the values of any `.sailsrc` files will also be merged into the config overrides. These override values will take precedence over any user configuration encountered in the next step. ### (2) Load user configuration Unless the `userconfiguration` hook is explicitly disabled, Sails will next load the configuration files in the `config` folder (and subfolders) underneath the current working directory. See [**Concepts > Configuration**](https://sailsjs.com/documentation/concepts/configuration) for more details about user configuration. Configuration settings from step 1 will be merged on top of these values to form the `sails.config` object. ### (3) Load hooks Next, Sails will load the other hooks. [Core hooks](https://sailsjs.com/documentation/concepts/extending-sails/hooks#?types-of-hooks) will load first, followed by user hooks and installable hooks. Note that hooks typically include configuration of their own which will be used as _default values_ in `sails.config`. For example, if no `port` setting is configured by this point, the `http` hook's default value of 1337 will be used. ### (4) Assemble router Sails prepares the core Router, then emits multiple events on the `sails` object informing hooks that they can safely bind routes. ### (5) Expose global variables After all hooks have initialized, Sails exposes global variables (by default: `sails` object, models, services, `_`, and `async`). ### (6) Initialize app runtime > This step does not run when `sails.load()` is used programmatically. > To run the initialization step, use `sails.lift()` instead. + Run the bootstrap function (`sails.config.bootstrap`) + Start attached servers (by default, Express and Socket.io) ### FAQ + What is the difference between `sails.lift()` and `sails.load()`? + `lift()` === `load()` + `initialize()`. It does everything `load()` does, plus it starts any attached servers (e.g. HTTP) and logs a picture of a boat.