最簡單的 FastAPI 檔案可能看起來像這樣：

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

將其複製到一個名為 `main.py` 的文件中。

執行即時重新載入伺服器（live server）：

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>

// license that can be found in the LICENSE file.

// This input was created by taking the ppc64 testcase and modified
// by hand.

#include "../../../../../runtime/textflag.h"

TEXT foo(SB),DUPOK|NOSPLIT,$0
//
// branch
//
//	LBRA rel
//	{
//		outcode(int($1), &nullgen, 0, &$2);
//	}
	BEQ	R1, 2(PC)
label0:
	JMP	1(PC)		// JMP 1(PC)	// 10000001
	BEQ	R1, 2(PC)

Do mesmo modo, você pode sobreescrever o `HTTPException`.

Por exemplo, você pode querer retornar uma *response* em *plain text* ao invés de um JSON para os seguintes erros:

{* ../../docs_src/handling_errors/tutorial004.py hl[3:4,9:11,22] *}

/// note | Detalhes Técnicos

Você pode usar `from starlette.responses import PlainTextResponse`.

$element.attr(SELECTOR_ARIA_ATTR)\n    const $body = $element.next(SELECTOR_EXPANDABLE_BODY).children().first().children()\n\n    $body.stop()\n    if ($type === 'true') {\n      $body.slideUp(time, () => {\n        $element.next(SELECTOR_EXPANDABLE_BODY).addClass('d-none')\n      })\n      $element.attr(SELECTOR_ARIA_ATTR, 'false')\n      $element.trigger($.Event(EVENT_COLLAPSED))\n    } else if ($type === 'false') {\n      $element.next(SELECTOR_EXPANDABLE_BODY).removeClass('d-none')\n      $body.slideDown(time)\n...

import java.time.format.DateTimeFormatter;
import java.util.Comparator;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import java.util.stream.Collectors;

import org.apache.commons.text.StringEscapeUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.app.web.base.login.FessCredential;

// Code generated by avx512test. DO NOT EDIT.

#include "../../../../../../runtime/textflag.h"

TEXT asmtest_avx512cd(SB), NOSPLIT, $0
	VPBROADCASTMB2Q K1, X25                            // 6262fe082ac9
	VPBROADCASTMB2Q K5, X25                            // 6262fe082acd
	VPBROADCASTMB2Q K1, X11                            // 6272fe082ad9
	VPBROADCASTMB2Q K5, X11                            // 6272fe082add

      long next = flip(array[i]);
      if (next > max) {
        max = next;
      }
    }
    return flip(max);
  }

  /**
   * Returns a string containing the supplied unsigned {@code long} values separated by {@code
   * separator}. For example, {@code join("-", 1, 2, 3)} returns the string {@code "1-2-3"}.
   *

H0, T0.D[0] VMOV H1, T3.D[0] ld4: TBZ $2, srcPtrLen, ld2 MOVW.W -4(srcPtr), H0 VEXT $12, T0.B16, ZERO.B16, T0.B16 VEXT $12, T3.B16, ZERO.B16, T3.B16 VMOV H0, T0.S[0] VMOV H1, T3.S[0] ld2: TBZ $1, srcPtrLen, ld1 MOVH.W -2(srcPtr), H0 VEXT $14, T0.B16, ZERO.B16, T0.B16 VEXT $14, T3.B16, ZERO.B16, T3.B16 VMOV H0, T0.H[0] VMOV H1, T3.H[0] ld1: TBZ $0, srcPtrLen, ld0 MOVB.W -1(srcPtr), H0 VEXT $15, T0.B16, ZERO.B16, T0.B16 VEXT $15, T3.B16, ZERO.B16, T3.B16 VMOV H0, T0.B[0] VMOV H1, T3.B[0] ld0: MOVD ZR,...

  /**
   * Returns a string containing the supplied {@code int} values separated by {@code separator}. For
   * example, {@code join("-", 1, 2, 3)} returns the string {@code "1-2-3"}.
   *
   * @param separator the text that should appear between consecutive values in the resulting string
   *     (but not at the start or end)
   * @param array an array of {@code int} values, possibly empty
   */

Jedes spezifische Beispiel-`dict` in den `examples` kann Folgendes enthalten:

* `summary`: Kurze Beschreibung für das Beispiel.
* `description`: Eine lange Beschreibung, die Markdown-Text enthalten kann.
* `value`: Dies ist das tatsächlich angezeigte Beispiel, z. B. ein `dict`.