# First Steps { #first-steps }

The simplest FastAPI file could look like this:

{* ../../docs_src/first_steps/tutorial001.py *}

Copy that to a file `main.py`.

Run the live server:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:solid">main.py</u>

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting development server 🚀

Sebastián Ramírez <******@****.***> 1731896744 +0100

//
// Scanning stops if the function returns an error, in which case some of
// the input may be discarded. If that error is [ErrFinalToken], scanning
// stops with no error. A non-nil token delivered with [ErrFinalToken]
// will be the last token, and a nil token with [ErrFinalToken]
// immediately stops the scanning.
//

	DB.Create(&users)

	var users1, users2, users3 []User
	DB.Scopes(NameIn1And2).Find(&users1)
	if len(users1) != 2 {
		t.Errorf("Should found two users's name in 1, 2, but got %v", len(users1))
	}

	DB.Scopes(NameIn1And2, NameIn2And3).Find(&users2)
	if len(users2) != 1 {
		t.Errorf("Should found one user's name is 2, but got %v", len(users2))
	}

	DB.Scopes(NameIn([]string{users[0].Name, users[2].Name})).Find(&users3)

     * @param scopesToCollect The dependency scopes that should be collected, may be {@code null}.
     * @param scopesToResolve The dependency scopes that should be collected and also resolved, may be {@code null}.
     * @param session         The current build session, must not be {@code null}.
     * @return The transitive dependencies of the specified project that match the requested scopes, never {@code null}.

    - advanced/response-headers.md
    - advanced/response-change-status-code.md
    - advanced/advanced-dependencies.md
    - Advanced Security:
      - advanced/security/index.md
      - advanced/security/oauth2-scopes.md
      - advanced/security/http-basic-auth.md
    - advanced/using-request-directly.md
    - advanced/dataclasses.md
    - advanced/middleware.md
    - advanced/sub-applications.md
    - advanced/behind-a-proxy.md

        pyver: ['3.9', '3.10', '3.11', '3.12']
    steps:
      - name: Stop old running containers (if any)
        shell: bash
        run: |
          running_containers=$(docker ps -q) && \
          if [[ $running_containers == "" ]]; then
            echo "No running containers";
          else
            echo "Running container(s) found" && \
            docker stop $running_containers;
          fi

        verify(out, timeout(1000)).write(payload, 0, 3);

        // Stop the thread by sending n = -1
        synchronized (w) {
            w.write(new byte[0], -1, out);
        }

        w.join(2000);
        assertFalse(w.isAlive(), "WriterThread should stop after -1 sentinel");
    }

    @Test
    @DisplayName("WriterThread surfaces SmbException via checkException")

		flag.PrintDefaults()
		return
	}

	// The credentials package in minio-go provides an interface to call the
	// STS API.

	// Initialize credential options
	var stsOpts cr.STSAssumeRoleOptions
	stsOpts.AccessKey = minioUsername
	stsOpts.SecretKey = minioPassword

	if sessionPolicyFile != "" {
		var policy string
		if f, err := os.Open(sessionPolicyFile); err != nil {

 *
 * <h3>Derived steps</h3>
 *
 * A {@code ClosingFuture} step can be derived from one or more input {@code ClosingFuture} steps in
 * ways similar to {@link FluentFuture}s:
 *
 * <ul>
 *   <li>by transforming the value from a successful input step,
 *   <li>by catching the exception from a failed input step, or
 *   <li>by combining the results of several input steps.
 * </ul>
 *