---

"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

Use it the same way you would use the `FastAPI` class:

```Python hl_lines="6  11  16" title="app/routers/users.py"
{!../../docs_src/bigger_applications/app/routers/users.py!}
```

You can think of `APIRouter` as a "mini `FastAPI`" class.

All the same options are supported.

All the same `parameters`, `responses`, `dependencies`, `tags`, etc.

/// tip

---

"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

  //    try { /* monitor locked and guard satisfied here */ }
  //    finally { guard.unlock(); }
  // Here are Justin's design notes about this:
  //
  // This idea has come up from time to time, and I think one of my
  // earlier versions of Monitor even did something like this. I ended
  // up strongly favoring the current interface.
  //
  // I probably can't remember all the reasons (it's possible you

        // This may cause issues when an anonymous class is created inside a static initializer,
        // and the class's constructor's first parameter happens to be the enclosing class.
        // In such case, we may mistakenly think that the class is within a non-static context
        // and the first parameter is the hidden 'this'.
        return declaringClass.getEnclosingClass() != null
            && !Modifier.isStatic(declaringClass.getModifiers());

            if ((n != byteCount) && (LogStream.level >= 5)) {
                log.println("byteCount=" + byteCount + " but readBytesWireFormat returned " + n);
            }
            // Don't think we can rely on n being correct here. Must use byteCount.
            // Last paragraph of section 3.13.3 eludes to this.

            bufferIndex += byteCount;
        }

        length = bufferIndex - start;

 *
 * @since 2.0
 */
@DoNotMock("Use ImmutableList.of or another implementation")
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
// TODO(kevinb): I think we should push everything down to "BaseImmutableCollection" or something,
// just to do everything we can to emphasize the "practically an interface" nature of this class.

---

"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

        }
      } finally {
        // Important to null this out here - if we did *not* execute inline, we might still
        // run() on the same thread that called execute() - such as in a thread pool, and think
        // that it was happening inline. As a side benefit, avoids holding on to the Thread object
        // longer than necessary.
        submitting = null;
      }
    }

             * request. However the chances are slim and the
             * retry code should ensure the overall request
             * is serviced. The alternative complicates things
             * more than I think is worth it.
             */

            if (this.socket != null) {
                this.socket.close();
                this.socket = null;
            }
            this.thread = null;