///

### 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.

# Sub Applications - Mounts { #sub-applications-mounts }

If you need to have two independent FastAPI applications, with their own independent OpenAPI and their own docs UIs, you can have a main app and "mount" one (or more) sub-application(s).

## Mounting a **FastAPI** application { #mounting-a-fastapi-application }

# How To - Recipes { #how-to-recipes }

Here you will see different recipes or "how to" guides for **several topics**.

Most of these ideas would be more or less **independent**, and in most cases you should only need to study them if they apply directly to **your project**.

If something seems interesting and useful to your project, go ahead and check it, but otherwise, you might probably just skip them.

/// tip

# Benchmarks { #benchmarks }

Independent TechEmpower benchmarks show **FastAPI** applications running under Uvicorn as [one of the fastest Python frameworks available](https://www.techempower.com/benchmarks/#section=test&runid=7464e520-0dc2-473d-bd34-dbdfd7e85911&hw=ph&test=query&l=zijzen-7), only below Starlette and Uvicorn themselves (used internally by FastAPI).

But when checking benchmarks and comparisons you should keep the following in mind.

 *
 * <p>{@code CharSource} provides two kinds of methods:
 *
 * <ul>
 *   <li><b>Methods that return a reader:</b> These methods should return a <i>new</i>, independent
 *       instance each time they are called. The caller is responsible for ensuring that the
 *       returned reader is closed.
 *   <li><b>Convenience methods:</b> These are implementations of common operations that are

import jakarta.servlet.http.HttpServletResponse;

/**
 * Filter for CPU load-based request control.
 * Returns HTTP 429 (Too Many Requests) when CPU usage exceeds configurable thresholds.
 * Web and API requests have independent threshold settings.
 */
public class LoadControlFilter implements Filter {

    private static final Logger logger = LogManager.getLogger(LoadControlFilter.class);

    private static final int RETRY_AFTER_SECONDS = 60;

        StackTraceElement[] newStackTrace = exception.getStackTrace();
        assertNotNull(newStackTrace);
    }

    @Test
    public void test_multipleInstances() {
        // Test that multiple instances are independent
        String message1 = "First exception";
        String message2 = "Second exception";

        UnsupportedSearchException exception1 = new UnsupportedSearchException(message1);

 *
 *  * **Canceled:** the web socket connection failed. Messages that were successfully enqueued by
 *    either peer may not have been transmitted to the other.
 *
 * Note that the state progression is independent for each peer. Arriving at a gracefully-closed
 * state indicates that a peer has sent all of its outgoing messages and received all of its

            assertEquals("User is not found: testuser", e.getCause().getMessage());
        }
    }

    @Test
    public void test_multipleInstances() {
        // Test that multiple instances are independent
        FessUserNotFoundException exception1 = new FessUserNotFoundException("user1");
        FessUserNotFoundException exception2 = new FessUserNotFoundException("user2");

        assertNotSame(exception1, exception2);

      /*
       * We need not worry about class unloading under Android. Plus, this approach doesn't always
       * work under Android.
       *
       * (Clearing inheritableThreadLocals could still be useful independent of class unloading, but
       * that's a larger problem, which we don't attempt to solve anywhere else in Guava.)
       */
      return null;
    }
    try {