### What is "Mounting" { #what-is-mounting }

"Mounting" means adding a complete "independent" application in a specific path, that then takes care of handling all the sub-paths.

This is different from using an `APIRouter` as a mounted application is completely independent. The OpenAPI and docs from your main application won't include anything from the mounted application, etc.

You can read more about this in the [Advanced User Guide](../advanced/index.md).

     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

                                    "content": {"application/json": {"schema": {}}},
                                },
                                "422": {
                                    "description": "Validation Error",
                                    "content": {
                                        "application/json": {
                                            "schema": {

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

# Global Dependencies { #global-dependencies }

For some types of applications you might want to add dependencies to the whole application.

Similar to the way you can [add `dependencies` to the *path operation decorators*](dependencies-in-path-operation-decorators.md), you can add them to the `FastAPI` application.

In that case, they will be applied to all the *path operations* in the application:

{* ../../docs_src/dependencies/tutorial012_an_py310.py hl[17] *}

### Bigger Errors - Crashes { #bigger-errors-crashes }

Nevertheless, there might be cases where we write some code that **crashes the entire application** making Uvicorn and Python crash. 💥

### Top-level application { #top-level-application }

First, create the main, top-level, **FastAPI** application, and its *path operations*:

{* ../../docs_src/sub_applications/tutorial001_py310.py hl[3, 6:8] *}

### Sub-application { #sub-application }

Then, create your sub-application, and its *path operations*.

     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Application startup complete.
```

</div>

Dans la sortie, il y a une ligne semblable à :

```hl_lines="4"
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

Cette ligne montre l’URL où votre application est servie, sur votre machine locale.

     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.
     <span style="background-color:#007166"><font color="#D3D7CF"> INFO </font></span>  Waiting for application startup.