---
title: "メールを送信する"
version: 6.1
locale: ja
source: https://docs.djangoproject.com/ja/6.1/topics/email/
canonical: https://djangodocs.dev/ja/6.1/topics/email/
---
# メールを送信する

Django provides wrappers for Python's [`email`](https://docs.python.org/3/library/email.html#module-email) and [`smtplib`](https://docs.python.org/3/library/smtplib.html#module-smtplib) modules
to simplify composing and sending email. Django's email framework also supports
swapping in different delivery mechanisms: you can direct email to the console
or a file during development and an SMTP server or email service provider in
production.

コードは `django.core.mail` モジュールにあります。

## 簡単な例

簡単なメール送信には [`send_mail()`](#django.core.mail.send_mail) を使用します。たとえば、プレーンテキストのメッセージを送信するには、次のようにします。

```
from django.core.mail import send_mail

send_mail(
    "Subject here",
    "Here is the message.",
    "from@example.com",
    ["to@example.com"],
)
```

When additional email sending functionality is needed, use the
[EmailMessage](#topic-email-message) or [`EmailMultiAlternatives`](#django.core.mail.EmailMultiAlternatives)
class. For example, to send a multipart email that includes both HTML and plain
text versions with a specific template and custom headers, you can use the
following approach:

```
from django.core.mail import EmailMultiAlternatives
from django.template.loader import render_to_string

# First, render the plain text content.
text_content = render_to_string(
    "templates/emails/my_email.txt",
    context={"my_variable": 42},
)

# Secondly, render the HTML content.
html_content = render_to_string(
    "templates/emails/my_email.html",
    context={"my_variable": 42},
)

# Then, create a multipart email instance.
msg = EmailMultiAlternatives(
    subject="Subject here",
    body=text_content,
    from_email="from@example.com",
    to=["to@example.com"],
    headers={"List-Unsubscribe": "<mailto:unsub@example.com>"},
)

# Lastly, attach the HTML content to the email instance and send.
msg.attach_alternative(html_content, "text/html")
msg.send()
```

## Configuring email

New Django projects are not configured to send email by default. Instead, email
is printed to the console as a development aid (for projects created with
[`startproject`](/ja/6.1/ref/django-admin/#django-admin-startproject)) or results in a `MailerDoesNotExist` error (when the
[`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting isn't defined).

Use the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting to tell Django how to send email. For
example, to send through an SMTP server running on the local machine:

```
MAILERS = {
    "default": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "localhost",
        },
    },
}
```

Django abstracts the email sending process into an "email backend" class.
[メールのバックエンド](#topic-email-backends) lists the email backends that come with Django.

The example above uses Django's [SMTP email backend](#topic-email-smtp-backend), which sends using the standard [SMTP](https://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol) protocol.
This backend is useful for many production configurations, including SMTP
servers in your own infrastructure and most commercial email service providers
(ESPs). There are also [third-party email backends](#topic-third-party-email-backends) available that integrate directly with ESP
APIs or add other sending features.

During development or testing you often don't want to send email at all.
Django's test runner [automatically overrides](/ja/6.1/topics/testing/tools/#topics-testing-email) the
[`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) configuration to substitute Django's [memory email
backend](#topic-email-memory-backend). This prevents test cases from sending
real email and gives them access to the messages that would have been sent.
[開発用にメールを設定する](#configuring-email-for-development) discusses some other
approaches.

> **Changed in Django 6.1**
>
> In earlier releases, Django defaulted to sending email through an SMTP
> server running on localhost, using the now-deprecated
> [`EMAIL_BACKEND`](/ja/6.1/ref/settings/#std-setting-EMAIL_BACKEND) and related settings.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: Until Django 7.0, if the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting is not defined then the
> earlier behavior still applies: Django will default to using an SMTP server
> on localhost (but will issue deprecation warnings). Starting in Django 7.0,
> attempts to send email without [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) defined will result in a
> `MailerDoesNotExist` error.
>
> Existing projects can opt into the new behavior early by adding
> [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) to `settings.py`. See [Migrating email to mailers](/ja/6.1/howto/mailers-migration/#migrating-to-mailers).

### Multiple mailers

Sometimes different types of email need to be sent in different ways: e.g.,
internal vs. external email, different SMTP servers for users in different
regions, using different services for transactional notifications and bulk
marketing email, etc.

The [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting can define multiple mail configurations. For
example:

```
import os

MAILERS = {
    "default": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "smtp.example.net",
            "use_tls": True,
            "username": os.environ["EMAIL_ACCOUNT_ID"],
            "password": os.environ["EMAIL_API_KEY"],
        },
    },
    "notifications": {
        "BACKEND": "example.third.party.EmailBackend",
        "OPTIONS": {
            "api_key": os.environ["THIRD_PARTY_API_KEY"],
            "region": "eu",
        },
    },
    "admin": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "localhost",
        },
    },
}
```

This defines three mailer configurations:

- `"default"` sends through an SMTP server at `smtp.example.net` with a TLS
  secured connection. It reads an account id and API key from environment
  variables and uses them as the SMTP authentication username and password.
  (Many SMTP services use some variation of this authentication scheme.)
- `"notifications"` sends through a hypothetical commercial email service,
  using a third-party EmailBackend that connects directly to their API.
  (See [Third-party backends](#topic-third-party-email-backends) for pointers on locating real,
  community maintained email backend packages.)
- `"admin"` sends through an SMTP server running on `localhost`, with no
  other options required.

With this configuration, you can provide the `using` argument to Django's
[email sending functions](#topic-email-sending) to specify a particular
mailer configuration:

```
from django.core.mail import send_mail

send_mail(
    "Account activated",
    "Congratulations, you're all ready to use our Django app!",
    "from@example.com",
    ["user@example.com"],
    using="notifications",
)
```

If `using` is not specified, Django uses the mailer defined for the
`"default"` configuration.

With reusable apps or Django features that send email for you, there may be an
option to use a specific mailer configuration. For example, Django's logging
[`AdminEmailHandler`](/ja/6.1/ref/logging/#django.utils.log.AdminEmailHandler) allows specifying the mailer
configuration in its `using` option.

## Sending messages

`django.core.mail` provides functions for conveniently sending email, as
well as classes for building and sending more complex email messages with
attachments and multiple content types.

> **Note**
>
> `django.core.mail` で送信されるメールの文字セットは、[`DEFAULT_CHARSET`](/ja/6.1/ref/settings/#std-setting-DEFAULT_CHARSET) 設定の値にセットされます。

### `send_mail()`

#### `send_mail(subject, message, from_email, recipient_list, * (Keyword-only parameters separator (PEP 3102)), fail_silently=False, auth_user=None, auth_password=None, connection=None, html_message=None)`

`django.core.mail.send_mail()` sends a single email message.

`subject`、`message`、`from_email`、`recipient_list` の 4 つの引数は必須です。

- `subject`: 文字列。
- `message`: 文字列。
- `from_email`: 文字列。もし `None` なら、 Django は [`DEFAULT_FROM_EMAIL`](/ja/6.1/ref/settings/#std-setting-DEFAULT_FROM_EMAIL) 設定の値を使います。
- `recipient_list`: メールアドレスを表す文字列のリスト。`recipient_list` の各メンバーは、メールメッセージの "To:" フィールドで他の受信者を見ることができます。

The following parameters are optional, and must be given as keyword arguments
if used.

- `fail_silently`: A boolean, default `False`. If set `True`,
  `send_mail()` will suppress some errors during sending. (The exact
  exceptions ignored depend on the email backend in use.)
- `auth_user`: SMTP サーバー認証のためのユーザー名で、省略可能。指定されなかった場合、Django [`EMAIL_HOST_USER`](/ja/6.1/ref/settings/#std-setting-EMAIL_HOST_USER) 設定の値を使います。
- `auth_password`: SMTP サーバー認証のためのパスワードで、省略可能。指定されなかった場合、Django は [`EMAIL_HOST_PASSWORD`](/ja/6.1/ref/settings/#std-setting-EMAIL_HOST_PASSWORD) 設定の値を使います。
- `connection`: メール送信のために使うバックエンドで、省略可能。指定しなかった場合、デフォルトのバックエンドのインスタンスが使われます。詳しくは [メールのバックエンド](#topic-email-backends) を参照してください。
- `html_message`: `html_message` が指定された場合、送信されるメールは `multipart/alternative` となり、`text/plain` コンテンツタイプを持つ `message` と `text/html` コンテンツタイプを持つ `html_message` を合わせ持つものになります。
- `using`: An optional [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) alias to use to send the mail. If
  unspecified, the default mailer configuration will be used.

`fail_silently`, `auth_user`, `auth_password`, and `connection` are not
allowed with the `using` argument.

返り値は、送信に成功したメッセージの数です (送信されるメッセージが 1 つだけの場合もあるため、`0` や `1` になることもあります)。

> **Deprecated since Django 6.0**
>
> バージョン 6.0 で非推奨: Passing `fail_silently` and later parameters as positional arguments is
> deprecated.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: The `fail_silently`, `auth_user`, `auth_password`, and `connection`
> arguments are deprecated. In most cases they can be replaced by `using`
> with an appropriate [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) configuration. See
> [Replacing fail\_silently](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-fail-silently),
> [Replacing auth\_user and auth\_password](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-auth), and
> [Replacing get\_connection() and connection arguments](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-get-connection).

> **Changed in Django 6.1**
>
> The `using` argument was added.
>
> Older versions ignored `fail_silently=True`, `auth_user`,
> and `auth_password` when a `connection` was also provided.
> This now raises a `TypeError`.

### `send_mass_mail()`

#### `send_mass_mail(datatuple, * (Keyword-only parameters separator (PEP 3102)), fail_silently=False, auth_user=None, auth_password=None, connection=None, using=None)`

`django.core.mail.send_mass_mail()` は、大量のメール送信を扱うために用意されています。

`datatuple` はメッセージの集合を表すタプルです。タプル内の各要素は、それぞれ1種類のメッセージを表すタプルであり、次の形式を持ちます。

```
(subject, message, from_email, recipient_list)
```

`fail_silently`, `auth_user`, `auth_password` and `connection` have the
same functions as in [`send_mail()`](#django.core.mail.send_mail). They must be given as keyword arguments
if used, and are not allowed with the `using` argument.

The keyword argument `using` is an optional [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) alias to use
to send the mail. If unspecified, the default mailer configuration will be
used.

Each separate element of `datatuple` results in a separate email message.
As in [`send_mail()`](#django.core.mail.send_mail), recipients in the same `recipient_list` will all see
the other addresses in the email messages' "To:" field.

たとえば、次のコードは異なる 2 つのメッセージを 異なる 2 つの受信者のセットに送信します。しかし、メールサーバーへのコネクションは 1 つしか開かれません。

```
message1 = (
    "Subject here",
    "Here is the message",
    "from@example.com",
    ["first@example.com", "other@example.com"],
)
message2 = (
    "Another Subject",
    "Here is another message",
    "from@example.com",
    ["second@test.com"],
)
send_mass_mail((message1, message2))
```

戻り値は、メッセージ送信に成功した数です。

> **Deprecated since Django 6.0**
>
> バージョン 6.0 で非推奨: Passing `fail_silently` and later parameters as positional arguments is
> deprecated.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: The `fail_silently`, `auth_user`, `auth_password`, and `connection`
> arguments are deprecated. In most cases they can be replaced by `using`
> with an appropriate [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) configuration. See
> [Replacing fail\_silently](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-fail-silently),
> [Replacing auth\_user and auth\_password](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-auth), and
> [Replacing get\_connection() and connection arguments](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-get-connection).

> **Changed in Django 6.1**
>
> The `using` argument was added.
>
> Older versions ignored `fail_silently=True`, `auth_user`,
> and `auth_password` when a `connection` was also provided.
> This now raises a `TypeError`.

#### `send_mass_mail()` と `send_mail()` の比較

The main difference between [`send_mass_mail()`](#django.core.mail.send_mass_mail) and repeatedly calling
[`send_mail()`](#django.core.mail.send_mail) is that [`send_mail()`](#django.core.mail.send_mail) opens a connection to the mail
server each time it's executed, while [`send_mass_mail()`](#django.core.mail.send_mass_mail) uses a single
connection for all of its messages. This makes [`send_mass_mail()`](#django.core.mail.send_mass_mail) slightly
more efficient.

[`send_mail()`](#django.core.mail.send_mail) with multiple `to` addresses sends a single email message,
with `john@example.com` and `jane@example.com` both appearing in the "To:"
field:

```
send_mail(
    "Subject",
    "Message.",
    "from@example.com",
    ["john@example.com", "jane@example.com"],
)
```

[`send_mass_mail()`](#django.core.mail.send_mass_mail) sends a separate message per `datatuple` element, so
`john@example.com` and `jane@example.com` each receive their own email:

```
datatuple = (
    ("Subject", "Message.", "from@example.com", ["john@example.com"]),
    ("Subject", "Message.", "from@example.com", ["jane@example.com"]),
)
send_mass_mail(datatuple)
```

### `mail_admins()`

#### `mail_admins(subject, message, * (Keyword-only parameters separator (PEP 3102)), fail_silently=False, connection=None, html_message=None, using=None)`

`django.core.mail.mail_admins()` は、[`ADMINS`](/ja/6.1/ref/settings/#std-setting-ADMINS) 設定で定義されているサイト管理者 (admin) に対してメールを送信するためのショートカットです。

`mail_admins()` は件名の前に [`EMAIL_SUBJECT_PREFIX`](/ja/6.1/ref/settings/#std-setting-EMAIL_SUBJECT_PREFIX) 設定の値を付けますが、デフォルトでは `"[Django] "` です。

メールの "From: " ヘッダは [`SERVER_EMAIL`](/ja/6.1/ref/settings/#std-setting-SERVER_EMAIL) 設定の値になります。

このメソッドは利便性と読みやすさのために存在します。

`html_message` が指定された場合、送信されるメールは `multipart/alternative` となり、`text/plain` コンテンツタイプを持つ `message` と `text/html` コンテンツタイプを持つ `html_message` を合わせ持つものになります。

The keyword argument `using` is an optional [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) alias to use
to send the mail. If unspecified, the default mailer configuration will be
used.

> **Deprecated since Django 6.0**
>
> バージョン 6.0 で非推奨: Passing `fail_silently` and later parameters as positional arguments is
> deprecated.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: The `fail_silently` and `connection` arguments are deprecated. In most
> cases they can be replaced by `using` with an appropriate
> [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) configuration. See
> [Replacing fail\_silently](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-fail-silently) and
> [Replacing get\_connection() and connection arguments](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-get-connection).

> **Changed in Django 6.1**
>
> The `using` argument was added.
>
> Older versions ignored `fail_silently=True` when a `connection`
> was also provided. This now raises a `TypeError`.

### `mail_managers()`

#### `mail_managers(subject, message, * (Keyword-only parameters separator (PEP 3102)), fail_silently=False, connection=None, html_message=None, using=None)`

`django.core.mail.mail_managers()` は、`mail_admins()` とほぼ同じで、[`MANAGERS`](/ja/6.1/ref/settings/#std-setting-MANAGERS) 設定で定義されているサイト管理者 (manager) にメールを送信します。

The keyword argument `using` is an optional [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) alias to use
to send the mail. If unspecified, the default mailer configuration will be
used.

> **Deprecated since Django 6.0**
>
> バージョン 6.0 で非推奨: Passing `fail_silently` and later parameters as positional arguments is
> deprecated.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: The `fail_silently` and `connection` arguments are deprecated. In most
> cases they can be replaced by `using` with an appropriate
> [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) configuration. See
> [Replacing fail\_silently](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-fail-silently) and
> [Replacing get\_connection() and connection arguments](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-get-connection).

> **Changed in Django 6.1**
>
> The `using` argument was added.
>
> Older versions ignored `fail_silently=True` when a `connection`
> was also provided. This now raises a `TypeError`.

### `EmailMessage` クラス

Django's [`send_mail()`](#django.core.mail.send_mail) and [`send_mass_mail()`](#django.core.mail.send_mass_mail) functions are actually
thin wrappers that make use of the [`EmailMessage`](#django.core.mail.EmailMessage) class.

Not all features of the [`EmailMessage`](#django.core.mail.EmailMessage) class are available through the
[`send_mail()`](#django.core.mail.send_mail) and related wrapper functions. If you wish to use advanced
features, such as BCC'ed recipients, file attachments, or multi-part email,
you'll need to create [`EmailMessage`](#django.core.mail.EmailMessage) instances directly.

> **Note**
>
> This is a design feature. [`send_mail()`](#django.core.mail.send_mail) and related functions were
> originally the only interface Django provided. However, the list of
> parameters they accepted was slowly growing over time. It made sense to
> move to a more object-oriented design for email messages and retain the
> original functions only for backwards compatibility.

[`EmailMessage`](#django.core.mail.EmailMessage) is responsible for creating the email message itself. The
[email backend](#topic-email-backends) is then responsible for sending the
email.

For convenience, [`EmailMessage`](#django.core.mail.EmailMessage) provides a [`send()`](#django.core.mail.EmailMessage.send)
method for sending a single email. If you need to send multiple messages, the
email backend API [provides an alternative](#topics-sending-multiple-emails).

#### `class EmailMessage`

The `EmailMessage` class is initialized with the following
parameters. All parameters are optional and can be set at any time prior
to calling the [`send()`](#django.core.mail.EmailMessage.send) method.

The first four parameters can be passed as positional or keyword arguments,
but must be in the given order if positional arguments are used:

- `subject`: メールの件名の行。
- `body`: 本文のテキスト。プレーンテキストのメッセージでなければなりません。
- `from_email`: The sender's address. Both `fred@example.com` and
  `"Fred" <fred@example.com>` forms are supported (see
  [Formatting email addresses](#formatting-addresses)). If omitted, the
  [`DEFAULT_FROM_EMAIL`](/ja/6.1/ref/settings/#std-setting-DEFAULT_FROM_EMAIL) setting is used.
- `to`: 受信者のメールアドレスのリストまたはタプル。

The following parameters must be given as keyword arguments if used:

- メールを送信するときに "Cc" ヘッダ内で使われる、受信者のアドレスのリストまたはタプル。
- `bcc`: A list or tuple of addresses used for blind carbon copies when
  sending the email.
- `reply_to`: メールを送信するときに "Reply-To" ヘッダ内で使われる、受信者のアドレスのリストまたはタプル。
- `attachments`: A list of attachments to put on the message. Each can
  be an instance of [`MIMEPart`](https://docs.python.org/3/library/email.message.html#email.message.MIMEPart) or
  [`EmailAttachment`](#django.core.mail.EmailAttachment), or a tuple with attributes
  `(filename, content, mimetype)`.

  > **Changed in Django 6.0**
  >
  > Support for [`MIMEPart`](https://docs.python.org/3/library/email.message.html#email.message.MIMEPart) objects in the
  > `attachments` list was added.

  > **Deprecated since Django 6.0**
  >
  > バージョン 6.0 で非推奨: Support for Python's legacy [`MIMEBase`](https://docs.python.org/3/library/email.mime.html#email.mime.base.MIMEBase)
  > objects in `attachments` is deprecated. Use
  > [`MIMEPart`](https://docs.python.org/3/library/email.message.html#email.message.MIMEPart) instead.
- `headers`: メッセージに追加するヘッダーの辞書。キーはヘッダ名、値はヘッダ値です。メールメッセージに対して適切なヘッダ名と値にするのは、呼び出す側の責任です。対応する属性は `extra_headers` です。
- `connection`: An [email backend](#topic-email-backends) instance.
  This parameter is ignored when using
  [send\_messages()](#topics-sending-multiple-emails).

  > **Deprecated since Django 6.1**
  >
  > バージョン 6.1 で非推奨: The `connection` argument is deprecated. Instead, define a
  > [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) configuration with the desired connection options,
  > and then call [`EmailMessage.send(using="...")`](#django.core.mail.EmailMessage.send) with that
  > configuration's alias. See [Migrating email to mailers](/ja/6.1/howto/mailers-migration/#migrating-to-mailers).

> **Deprecated since Django 6.0**
>
> バージョン 6.0 で非推奨: Passing all except the first four parameters as positional arguments is
> deprecated.

例:

```
from django.core.mail import EmailMessage

email = EmailMessage(
    subject="Hello",
    body="Body goes here",
    from_email="from@example.com",
    to=["to1@example.com", "to2@example.com"],
    bcc=["bcc@example.com"],
    reply_to=["another@example.com"],
    headers={"Message-ID": "foo"},
)
```

このクラスには以下のメソッドがあります。

#### `send(fail_silently=False, * (Keyword-only parameters separator (PEP 3102)), using=None)`

Sends the message. Returns `1` if the message was sent successfully,
otherwise `0`. (An empty list of recipients returns `0` -- it will
not raise an exception.)

The optional `using` keyword argument specifies a [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS)
alias to use to send the mail. If not given, the default mailer
configuration will be used.

If a deprecated connection was specified when the email was
constructed, that connection will be used. Providing both a connection
and `using` will raise an error.

If the deprecated keyword argument `fail_silently` is `True`,
certain backend-dependent exceptions while sending the message will be
ignored. Providing both `fail_silently` and `using` will raise an
error.

> **Changed in Django 6.1**
>
> The `using` argument was added.
>
> Older versions ignored `fail_silently=True` when a `connection`
> was also provided. This now raises a `TypeError`.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: The `fail_silently` argument is deprecated. See
> [Replacing fail\_silently](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-fail-silently) for alternatives.

#### `message(* (Keyword-only parameters separator (PEP 3102)), policy=email.policy.default)`

Constructs and returns a Python [`email.message.EmailMessage`](https://docs.python.org/3/library/email.message.html#email.message.EmailMessage)
object representing the message to be sent.

The keyword argument `policy` allows specifying the set of rules for
updating and serializing the representation of the message. It must be
an [`email.policy.Policy`](https://docs.python.org/3/library/email.policy.html#module-email.policy) object. Defaults to
[`email.policy.default`](https://docs.python.org/3/library/email.policy.html#email.policy.default). In certain cases you may want to use
[`SMTP`](https://docs.python.org/3/library/email.policy.html#email.policy.SMTP), [`SMTPUTF8`](https://docs.python.org/3/library/email.policy.html#email.policy.SMTPUTF8) or a custom
policy. For example, the [SMTP email backend](#topic-email-smtp-backend) uses the [`SMTP`](https://docs.python.org/3/library/email.policy.html#email.policy.SMTP) policy
to ensure `\r\n` line endings as required by the SMTP protocol.

If you ever need to extend Django's [`EmailMessage`](#django.core.mail.EmailMessage) class,
you'll probably want to override this method to put the content you
want into the Python EmailMessage object.

> **Changed in Django 6.0**
>
> The `policy` keyword argument was added and the return type was
> updated to an instance of [`EmailMessage`](https://docs.python.org/3/library/email.message.html#email.message.EmailMessage).

#### `recipients()`

Returns a list of all the recipients of the message, whether they're
recorded in the `to`, `cc` or `bcc` attributes. This is another
method you might need to override when subclassing, because the SMTP
server needs to be told the full list of recipients when the message
is sent. If you add another way to specify recipients in your class,
they need to be returned from this method as well.

#### `attach(filename, content, mimetype)`

#### `attach(mimepart)`

Creates a new attachment and adds it to the message. There are two ways
to call `attach()`:

- You can pass it three arguments: `filename`, `content` and
  `mimetype`. `filename` is the name of the file attachment as it
  will appear in the email, `content` is the data that will be
  contained inside the attachment and `mimetype` is the optional MIME
  type for the attachment. If you omit `mimetype`, the MIME content
  type will be guessed from the filename of the attachment.

  例:

  ```
  message.attach("design.png", img_data, "image/png")
  ```

  If you specify a `mimetype` of `message/rfc822`,
  `content` can be a [`django.core.mail.EmailMessage`](#django.core.mail.EmailMessage) or
  Python's [`email.message.EmailMessage`](https://docs.python.org/3/library/email.message.html#email.message.EmailMessage) or
  [`email.message.Message`](https://docs.python.org/3/library/email.compat32-message.html#email.message.Message).

  `text/` で始まる `mimetype` では、コンテンツは文字列であることが期待されます。バイナリデータはUTF-8でデコードされ、それが失敗した場合、MIMEタイプは `application/octet-stream` に変更され、データは変更されずに添付されます。
- Or for attachments requiring additional headers or parameters, you
  can pass `attach()` a single Python
  [`MIMEPart`](https://docs.python.org/3/library/email.message.html#email.message.MIMEPart) object. This will be attached
  directly to the resulting message. For example, to attach an inline
  image with a `Content-ID`:

  ```
  import email.utils
  from email.message import MIMEPart
  from django.core.mail import EmailMultiAlternatives

  message = EmailMultiAlternatives(...)
  image_data_bytes = ...  # Load image as bytes

  # Create a random Content-ID, including angle brackets
  cid = email.utils.make_msgid()
  inline_image = email.message.MIMEPart()
  inline_image.set_content(
      image_data_bytes,
      maintype="image",
      subtype="png",  # or "jpeg", etc. depending on the image type
      disposition="inline",
      cid=cid,
  )
  message.attach(inline_image)
  # Refer to Content-ID in HTML without angle brackets
  message.attach_alternative(f'… <img src="cid:{cid[1:-1]}"> …', "text/html")
  ```

  Python's [`email.contentmanager.set_content()`](https://docs.python.org/3/library/email.contentmanager.html#email.contentmanager.set_content) documentation
  describes the supported arguments for `MIMEPart.set_content()`.

  > **Changed in Django 6.0**
  >
  > Support for [`MIMEPart`](https://docs.python.org/3/library/email.message.html#email.message.MIMEPart) attachments was
  > added.

  > **Deprecated since Django 6.0**
  >
  > バージョン 6.0 で非推奨: Support for [`email.mime.base.MIMEBase`](https://docs.python.org/3/library/email.mime.html#email.mime.base.MIMEBase) attachments is
  > deprecated. Use [`MIMEPart`](https://docs.python.org/3/library/email.message.html#email.message.MIMEPart) instead.

#### `attach_file(path, mimetype=None)`

Creates a new attachment using a file from your filesystem. Call it
with the path of the file to attach and, optionally, the MIME type to
use for the attachment. If the MIME type is omitted, it will be guessed
from the filename. You can use it like this:

```
message.attach_file("/images/weather_map.png")
```

For MIME types starting with `text/`, binary data is handled
as in [`attach()`](#django.core.mail.EmailMessage.attach).

#### `class EmailAttachment`

メールに添付するファイルを保持するための名前付きタプルです。

この名前付きタプルは、下記のインデックスを持ちます：

- `filename`
- `content`
- `mimetype`

#### 代替のコンテンツタイプを送信する

##### 複数のバージョンを持つコンテンツを送る

It can be useful to include multiple versions of the content in an email; the
classic example is to send both text and HTML versions of a message. With
Django's email library, you can do this using the
[`EmailMultiAlternatives`](#django.core.mail.EmailMultiAlternatives) class.

#### `class EmailMultiAlternatives`

[`attach_alternative()`](#django.core.mail.EmailMultiAlternatives.attach_alternative) メソッドを通じて、メール本文の別バージョンを追加できるようにした [`EmailMessage`](#django.core.mail.EmailMessage) のサブクラスです。このクラスは [`EmailMessage`](#django.core.mail.EmailMessage) からすべてのメソッド（初期化メソッドも含む）をそのまま継承しています。

#### `alternatives`

A list of [`EmailAlternative`](#django.core.mail.EmailAlternative) named tuples.
This is particularly useful in tests:

```
self.assertEqual(len(msg.alternatives), 1)
self.assertEqual(msg.alternatives[0].content, html_content)
self.assertEqual(msg.alternatives[0].mimetype, "text/html")
```

代替コンテンツは、 [`attach_alternative()`](#django.core.mail.EmailMultiAlternatives.attach_alternative) メソッドを使って追加するか、コンストラクタに渡して指定する必要があります。

#### `attach_alternative(content, mimetype)`

メール内にメッセージ本文の代替の表現を添付します。

例えば、テキスト版とHTML版を組み合わせて送信する場合、次のようにします。

```
from django.core.mail import EmailMultiAlternatives

subject = "hello"
from_email = "from@example.com"
to = "to@example.com"
text_content = "This is an important message."
html_content = "<p>This is an <strong>important</strong> message.</p>"
msg = EmailMultiAlternatives(subject, text_content, from_email, [to])
msg.attach_alternative(html_content, "text/html")
msg.send()
```

#### `body_contains(text)`

指定された `text` が、メールの `body` およびすべての `text/*` MIME タイプの代替コンテンツに含まれているかどうかを示す真偽値を返します。

これはメールのテストのときに便利です。たとえば：

```
def test_contains_email_content(self):
    subject = "Hello World"
    from_email = "from@example.com"
    to = "to@example.com"
    msg = EmailMultiAlternatives(subject, "I am content.", from_email, [to])
    msg.attach_alternative("<p>I am content.</p>", "text/html")

    self.assertIs(msg.body_contains("I am content"), True)
    self.assertIs(msg.body_contains("<p>I am content.</p>"), False)
```

#### `class EmailAlternative`

メールコンテンツの別バージョンを保持するための名前付きタプルです。

この名前付きタプルは、下記のインデックスを持ちます：

- `content`
- `mimetype`

##### デフォルトのコンテンツタイプを変更する

By default, the MIME type of the `body` parameter in an [`EmailMessage`](#django.core.mail.EmailMessage)
is `"text/plain"`. It is good practice to leave this alone, because it
guarantees that any recipient will be able to read the email, regardless of
their mail client. However, if you are confident that your recipients can
handle an alternative content type, you can use the `content_subtype`
attribute on the [`EmailMessage`](#django.core.mail.EmailMessage) class to change the main content type.
The major type will always be `"text"`, but you can change the subtype. For
example:

```
msg = EmailMessage(subject, html_content, from_email, [to])
msg.content_subtype = "html"  # Main content is now text/html
msg.send()
```

### Safely sending email

Any public website that can send email will eventually be targeted by attempts
to abuse it for spam, phishing, or other malicious content. While a complete
discussion of vulnerabilities in sending email is beyond the scope of Django's
documentation, there are many references available on the web. Two good
starting points are:

- Princeton University's guidance on [preventing email abuse in web forms](https://sitebuilder.princeton.edu/site-administration/spam).
  Although this is an internal reference for users of Princeton's Drupal Site
  Builder, nearly all of its advice applies equally to sites built with Django
  (or any web framework).
- OWASP's [Email Validation and Verification in Identity Systems Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Email_Validation_and_Verification_Cheat_Sheet.html).
  This primarily covers using email in authentication contexts. While many of
  its recommendations are handled by [`django.contrib.auth`](/ja/6.1/topics/auth/#module-django.contrib.auth) and other
  Django features, items like rate limiting and securing email change workflows
  are the developer's responsibility.

Thinking through how email might be abused (and taking steps to mitigate it) is
especially important if your site can send to unverified addresses. Features
like newsletter sign-up, contact forms that cc or auto-reply to the sender, and
"share this page" can be attractive targets.

#### Formatting email addresses

Email addresses allow a "friendly" display name alongside the `user@domain`
address. For example, you could include your company name in the
[`DEFAULT_FROM_EMAIL`](/ja/6.1/ref/settings/#std-setting-DEFAULT_FROM_EMAIL) setting:

```
DEFAULT_FROM_EMAIL = '"Example, Inc." <contact@example.com>'
```

The double quotes around `"Example, Inc."` are needed so the comma isn't read
as separating two different addresses. A fixed address, written out by hand as
in the example above, is safe, but composing one from variable parts
(especially untrusted input) needs more care.

> **Warning**
>
> Never use string formatting to build an email address from variable parts.
> For example, `f'"{name}" <{email}>'` is **unsafe**.

Email address headers have complex syntax rules (much like HTML or SQL), so
constructing them by combining strings creates an injection vulnerability. Even
if you've [`validated`](/ja/6.1/ref/validators/#django.core.validators.EmailValidator) the format of `email`, an
attacker could exploit the `name` portion to inject additional addresses.

To avoid this, always use a well-tested library specifically meant to format
email addresses, like Python's [`email.headerregistry.Address`](https://docs.python.org/3/library/email.headerregistry.html#email.headerregistry.Address) class (the
replacement for the legacy [`formataddr()`](https://docs.python.org/3/library/email.utils.html#email.utils.formataddr) function, which does
not support internationalized domain names).

For example, to include a user's full name when sending them email (where
`user` is an instance of the default [`User`](/ja/6.1/ref/contrib/auth/#django.contrib.auth.models.User) model):

```
from django.core.mail import send_mail
from email.headerregistry import Address

def send_mail_to_user(user, subject, body, from_email=None):
    # Safely create an email address with the user's name.
    # (addr_spec is the technical term for the user@domain address.)
    address = Address(
        display_name=user.get_full_name(),
        addr_spec=user.email,
    )
    send_mail(subject, body, from_email, [address])
```

Django's built-in email backends support using
[`Address`](https://docs.python.org/3/library/email.headerregistry.html#email.headerregistry.Address) objects directly in any address field,
as shown here. So do many custom and third-party email backends. But if this
causes a `TypeError` or other problem with a particular backend, use
`str(address)` to convert the object to a safe, properly formatted string.

#### ヘッダインジェクションを防止する

[Email header injection](https://en.wikipedia.org/wiki/Email_injection) is a security exploit in which an attacker
manipulates email headers to change the intended sender or recipients, subject,
or potentially even the entire visible message body.

One type of header injection exploits address header syntax. You are
responsible for preventing this when constructing email addresses from
user-supplied input, as described in [Formatting email addresses](#formatting-addresses) above.

Another (perhaps better understood) attack, CRLF injection, uses carriage
return and line feed characters to insert additional headers into the email.
Django prevents this by raising a [`ValueError`](https://docs.python.org/3/library/exceptions.html#ValueError) if those characters appear
in any header field when trying to send the message.

> **Changed in Django 6.0**
>
> Older versions raised `django.core.mail.BadHeaderError` for some
> invalid headers. This has been replaced with `ValueError`.

Django's CRLF protection relies on using Python's modern
[`EmailPolicy`](https://docs.python.org/3/library/email.policy.html#email.policy.EmailPolicy) in Django's [`EmailMessage.message()`](#django.core.mail.EmailMessage.message).
Custom email backends that don't call that function, or that call it with the
legacy [`compat32`](https://docs.python.org/3/library/email.policy.html#email.policy.compat32) policy, are responsible for implementing
their own CRLF injection prevention.

### Sending many messages efficiently

SMTP コネクション (またはその他のネットワークコネクション) の確立とクローズは、負荷の高い処理です。 送信するメールがたくさんある場合は、メールを送信するたびにコネクションの生成と破棄を繰り返すのではなく、SMTP コネクションを再利用する方が効率的です。

There are two ways to tell an email backend to reuse a connection. Both involve
obtaining an email backend instance from [`mail.mailers`](#django.core.mail.mailers) and using the
[backend's API](#topic-email-backend-api).

The first approach is to use the backend's `send_messages()` method. This
takes a list of [`EmailMessage`](#django.core.mail.EmailMessage) (or subclass) instances, and sends them
all using that single connection.

For example, if you have a function called `get_notification_emails()` that
returns a list of [`EmailMessage`](#django.core.mail.EmailMessage) objects representing some periodic
email you wish to send out, you could send these emails using a single call to
`send_messages()`:

```
from django.core import mail

email_list = get_notification_emails()
# Use the default mailer. You could substitute
# mail.mailers["alias"] for a specific mailer.
backend = mail.mailers.default
backend.send_messages(email_list)
```

In this example, the call to `send_messages()` opens a connection on the
backend, sends the list of messages, and then closes the connection again.
(This is how [`send_mass_mail()`](#django.core.mail.send_mass_mail) is implemented.)

The second approach is to use the `open()` and `close()` methods on the
email backend to manually control the connection. `send_messages()` will not
open or close the connection if it is already open, so if you
manually open the connection, you can control when it is closed. For example:

```
from django.core import mail

# Use the "notifications" mailer configuration.
backend = mail.mailers["notifications"]

# Manually open the connection.
backend.open()

# Construct an email message. (Passing None as the third argument
# uses settings.DEFAULT_FROM_EMAIL as the "From:" address.)
email1 = mail.EmailMessage("Hi", "Message", None, ["to1@example.com"])
# Send the email. The connection was already open, so send_messages()
# leaves it open after sending.
backend.send_messages([email1])

# Construct and send two more messages. The connection is still open.
email2 = mail.EmailMessage("Hi", "Message", None, ["to2@example.com"])
email3 = mail.EmailMessage("Hi", "Message", None, ["to3@example.com"])
backend.send_messages([email2, email3])

# Because we opened it, we need to manually close the connection.
backend.close()
```

When you manually open a backend's connection, you are responsible for ensuring
it gets closed. The example above actually has a bug: if an exception occurs
while sending the messages, the connection will not be closed. This can be
fixed with a `try`-`finally` statement, but using the backend instance as a
context manager is preferable, as it automatically calls `open()` and
`close()` as needed.

This is equivalent to the previous example, but uses the backend as a
[context manager](https://docs.python.org/3/reference/datamodel.html#context-managers) to avoid leaving the connection open
on errors:

```
from django.core import mail

# Use mail.mailers[...] as a context manager.
with mail.mailers["notifications"] as backend:
    # The backend connection is automatically opened inside the context.
    email1 = mail.EmailMessage("Hi", "Message", None, ["to1@example.com"])
    backend.send_messages([email1])

    # The connection is still open, and is reused for the second send.
    email2 = mail.EmailMessage("Hi", "Message", None, ["to2@example.com"])
    email3 = mail.EmailMessage("Hi", "Message", None, ["to3@example.com"])
    backend.send_messages([email2, email3])

# After exiting the context (either normally or because of an error),
# the backend connection is automatically closed.
```

## メールのバックエンド

実際のメール送信は、メールバックエンドによって処理されます。

Django comes with several email backends. With the exception of the SMTP
backend, these are mainly useful during testing and development. If the
built-in backends don't meet your needs there are [third-party packages](#topic-third-party-email-backends) available. You can also subclass one of the
built-in backends to change its behavior, or even [write your own email
backend](#topic-custom-email-backend).

### SMTP バックエンド

The SMTP email backend connects to an SMTP server to send email. To use it, set
[`BACKEND`](/ja/6.1/ref/settings/#std-setting-MAILERS-BACKEND) to
`"django.core.mail.backends.smtp.EmailBackend"`.

The SMTP backend supports these [`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS):

- `"host"` (required): the SMTP server hostname or IP address.
- `"port"`: the port number to connect to on the SMTP host. If omitted,
  uses the standard port for the connection protocol depending on the
  `"use_tls"` and `"use_ssl"` options: `587` for TLS, `465` for SSL,
  or `25` for an unsecured connection.
- `"username"` and `"password"`: set these if your server requires SMTP
  authentication ("SMTP AUTH" credentials, sometimes called SMTP login).

  Although the username is often an email address, it should not be confused
  with default "From:" addresses. Those are defined by the
  [`DEFAULT_FROM_EMAIL`](/ja/6.1/ref/settings/#std-setting-DEFAULT_FROM_EMAIL) and [`SERVER_EMAIL`](/ja/6.1/ref/settings/#std-setting-SERVER_EMAIL) settings.
- `"use_tls"` or `"use_ssl"`: set one of these options to `True` to
  connect to the SMTP server using a secure protocol -- `"use_tls"` for
  explicit TLS or `"use_ssl"` for SSL (implicit TLS).
- `"ssl_certfile"` and `"ssl_keyfile"`: if the SMTP server's SSL/TLS
  connection requires client certificate authentication, use these options to
  specify the paths to a PEM-formatted certificate chain file and private key
  file. (The key file can be omitted if the certificate file includes the
  private key.)

  These options are not intended for use with a private certificate authority
  or self-signed SMTP server certificate. See
  [Private and self-signed SMTP server certificates](#topic-email-smtp-private-ca) below.

  Note that these options don't result in checking certificate validity. They
  are passed to the underlying SSL connection. Refer to the documentation of
  Python's [`ssl.SSLContext.wrap_socket()`](https://docs.python.org/3/library/ssl.html#ssl.SSLContext.wrap_socket) method for details on how the
  certificate chain file and private key file are handled.
- `"timeout"`: the timeout (in seconds) for connecting to the SMTP server and
  other blocking operations. If not specified, the value is obtained from
  [`socket.getdefaulttimeout()`](https://docs.python.org/3/library/socket.html#socket.getdefaulttimeout), which defaults to no timeout (`None`)
  meaning SMTP operations can block indefinitely.
- `"fail_silently"`: set to `True` to ignore certain errors while sending
  a message. All [`OSError`](https://docs.python.org/3/library/exceptions.html#OSError)s are ignored while opening the SMTP
  connection, and [`smtplib.SMTPException`](https://docs.python.org/3/library/smtplib.html#smtplib.SMTPException) errors are ignored while
  communicating with the server. This will suppress both transient network
  glitches and also serious configuration problems. However, it does not ignore
  *all* errors, and problems with serializing the message will not fail
  silently. (This option is available for backward compatibility but is not
  recommended for typical use.)

実装例:

```
MAILERS = {
    "default": {
        "BACKEND": "django.core.mail.backends.smtp.EmailBackend",
        "OPTIONS": {
            "host": "smtp.example.net",
            "use_tls": True,
            "username": "my-app",
            "password": os.environ["MY_APP_SMTP_PASSWORD"],
            "timeout": 10,
        },
    },
}
```

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: When the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting is not defined, Django uses the SMTP
> backend as the default mailer (the default [`EMAIL_BACKEND`](/ja/6.1/ref/settings/#std-setting-EMAIL_BACKEND)),
> connecting to localhost on port 25. This behavior will be removed in Django
> 7.0, which will not have a default mailer configuration.
>
> When the SMTP backend is used without [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) defined,
> the options listed above are obtained from the deprecated
> [`EMAIL_HOST`](/ja/6.1/ref/settings/#std-setting-EMAIL_HOST), [`EMAIL_PORT`](/ja/6.1/ref/settings/#std-setting-EMAIL_PORT), [`EMAIL_HOST_USER`](/ja/6.1/ref/settings/#std-setting-EMAIL_HOST_USER),
> [`EMAIL_HOST_PASSWORD`](/ja/6.1/ref/settings/#std-setting-EMAIL_HOST_PASSWORD), [`EMAIL_USE_TLS`](/ja/6.1/ref/settings/#std-setting-EMAIL_USE_TLS),
> [`EMAIL_USE_SSL`](/ja/6.1/ref/settings/#std-setting-EMAIL_USE_SSL), [`EMAIL_SSL_KEYFILE`](/ja/6.1/ref/settings/#std-setting-EMAIL_SSL_KEYFILE),
> [`EMAIL_SSL_CERTFILE`](/ja/6.1/ref/settings/#std-setting-EMAIL_SSL_CERTFILE), and [`EMAIL_TIMEOUT`](/ja/6.1/ref/settings/#std-setting-EMAIL_TIMEOUT) settings,
> respectively. (There is no setting equivalent to the `"fail_silently"`
> option.)

#### `class backends.smtp.EmailBackend`

Directly instantiating an `EmailBackend` class is not recommended. Use
[`mailers`](#django.core.mail.mailers) to obtain a backend instance.

When constructed directly (without going through [`mailers`](#django.core.mail.mailers)), the SMTP
`EmailBackend` class accepts the options listed above as keyword
arguments. Default values come from the corresponding, deprecated
`EMAIL_*` settings. `host` is not required and defaults to
`"localhost"`, and `port` defaults to `25` even if `use_tls` or
`use_ssl` is True.

When the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting is defined, attempting to directly
create an SMTP `EmailBackend` will raise an `AttributeError`.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: Directly constructing an instance of an `EmailBackend` class will be
> unsupported in Django 7.0. Undocumented use will result in different
> default argument handling compared to earlier releases.

#### Private and self-signed SMTP server certificates

If the SMTP server uses an SSL certificate from a private certificate authority
(CA), the CA's root certificate should be added to the system CA bundle on the
client (where Django is running). Likewise, if the server uses a self-signed
certificate, it should be added to the client's system CA bundle so it can be
trusted. (The SMTP backend's `"ssl_certfile"` option cannot be used for CA
roots or self-signed certificates.)

Follow platform-specific instructions for adding to the system CA bundle. If
modifying the system bundle is not possible or desired, an alternative is using
OpenSSL's `SSL_CERT_FILE` or `SSL_CERT_DIR` environment variables to
specify a custom certificate bundle.

For more complex scenarios, the SMTP backend can be subclassed to add root
certificates to its `ssl_context` using
[`ssl.SSLContext.load_verify_locations()`](https://docs.python.org/3/library/ssl.html#ssl.SSLContext.load_verify_locations).

### コンソールバックエンド

Instead of sending out real emails, the console backend writes the emails that
would be sent to the standard output. To use it, set [`BACKEND`](/ja/6.1/ref/settings/#std-setting-MAILERS-BACKEND) to `"django.core.mail.backends.console.EmailBackend"`.

The console backend supports these [`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS):

- `"stream"`: a stream-like object to write to. Defaults to `stdout`.
- `"fail_silently"`: set to `True` to ignore *all* errors while writing the
  message to the stream, including errors serializing the message. (This option
  is available for backward compatibility but is not recommended.)

このバックエンドはプロダクトでの使用を想定していません -- 開発中の利便性のために提供されています。

> **Changed in Django 6.1**
>
> The settings file created by [`startproject`](/ja/6.1/ref/django-admin/#django-admin-startproject) now defines
> [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) with the console backend as the default configuration.

### ファイルバックエンド

The file backend writes emails to a file. A new file is created for each new
session that is opened on this backend. To use it, set [`BACKEND`](/ja/6.1/ref/settings/#std-setting-MAILERS-BACKEND) to `"django.core.mail.backends.filebased.EmailBackend"`.

The file backend supports these [`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS):

- `"file_path"` (required): the directory to which the files are written. Can
  be a string or a [`pathlib.Path`](https://docs.python.org/3/library/pathlib.html#pathlib.Path) object. If the directory does not
  exist, the file backend will attempt to create it.
- `"fail_silently"`: set to `True` to ignore *all* errors while writing the
  message to the file -- including errors serializing the message -- but *not*
  errors related to ensuring the file path directory exists. (This option is
  available for backward compatibility but is not recommended.)

このバックエンドはプロダクトでの使用を想定していません -- 開発中の利便性のために提供されています。

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: When the file backend is used without the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting
> defined, it will get its `file_path` option from the
> [`EMAIL_FILE_PATH`](/ja/6.1/ref/settings/#std-setting-EMAIL_FILE_PATH) setting.

### インメモリーバックエンド

The `'locmem'` backend stores messages in a special attribute of the
`django.core.mail` module. The `outbox` attribute is created when the first
message is sent. It's a list with an [`EmailMessage`](#django.core.mail.EmailMessage) instance for each
message that would be sent. Messages in the outbox are annotated with a
`sent_using` attribute that identifies the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) alias used to
send the message.

To use the in-memory backend, set [`BACKEND`](/ja/6.1/ref/settings/#std-setting-MAILERS-BACKEND) to
`"django.core.mail.backends.locmem.EmailBackend"`. It does not support any
[`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS).

Django's test runner [automatically switches to this backend for testing](/ja/6.1/topics/testing/tools/#topics-testing-email).

このバックエンドはプロダクトでの使用を想定していません -- 開発とテストにおける利便性のために提供されています。

> **Changed in Django 6.1**
>
> The `sent_using` attribute was added to messages in the outbox.

### ダミーバックエンド

As the name suggests the dummy backend does nothing with your messages. To use
it, set [`BACKEND`](/ja/6.1/ref/settings/#std-setting-MAILERS-BACKEND) to
`"django.core.mail.backends.dummy.EmailBackend"`. It does not support any
[`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS).

このバックエンドはプロダクトでの使用を想定していません -- 開発中の利便性のために提供されています。

### Third-party backends

> **There are community-maintained solutions!**
>
> Django has a vibrant ecosystem. There are email backends
> highlighted on the [Community Ecosystem](https://www.djangoproject.com/community/ecosystem/#email-notifications) page. The Django Packages
> [Email grid](https://djangopackages.org/grids/g/email/) has even more options for you!

Third-party email backends are available that:

- Integrate directly with commercial email service providers' APIs (which often
  have extra functionality not available through SMTP).
- Offload email sending to asynchronous task queues.
- Add features to other email backends, such as enforcing do-not-send lists or
  logging sent messages.
- Provide development and debugging tools, such as sandbox capture and
  in-browser email previews.

### 独自のメールバックエンドを定義する

If you need to change how emails are sent you can write your own email backend.
To use a custom backend, set [`BACKEND`](/ja/6.1/ref/settings/#std-setting-MAILERS-BACKEND) to the Python
import path for your backend class and [`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS) to
any `__init__()` keyword arguments your backend supports.

Custom email backends should subclass `BaseEmailBackend` that is located in
the `django.core.mail.backends.base` module. A custom email backend must
implement the `send_messages(email_messages)` method. This method receives a
list of [`EmailMessage`](#django.core.mail.EmailMessage) instances and returns the number of successfully
delivered messages. If your backend has any concept of a persistent session or
connection, you should also implement the `open()` and `close()` methods.
Refer to `smtp.EmailBackend` for a reference implementation.

### メールバックエンドのインスタンスを取得する

The `mailers` factory in `django.core.mail` returns instances of email
backends.

#### `mailers`

> **New in Django 6.1**

You can access the mailers configured in the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting
through a dict-like object: `django.core.mail.mailers`:

```pycon
>>> from django.core.mail import mailers
>>> mailers["notifications"]
```

If the named key is not defined, a `MailerDoesNotExist` error will be
raised. Other configuration problems will raise an `InvalidMailer` error.

#### `mailers.default`

> **New in Django 6.1**

As a shortcut, the default mailer can be accessed through
`django.core.mail.mailers.default`:

```pycon
>>> from django.core.mail import mailers
>>> mailers.default
```

This is equivalent to `mailers["default"]`. If no default mailer has
been configured, a `MailerDoesNotExist` error will be raised.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: If the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting is not defined, `mailers.default`
> will create an email backend instance from the deprecated
> [`EMAIL_BACKEND`](/ja/6.1/ref/settings/#std-setting-EMAIL_BACKEND) and related settings. This supports backward
> compatibility with Django 6.0 and earlier.
>
> This behavior (and those settings) will be removed in Django 7.0.

#### `get_connection(backend=None, * (Keyword-only parameters separator (PEP 3102)), fail_silently=False, **kwargs)`

The deprecated `django.core.mail.get_connection()` function creates
and returns an instance of an email backend. Its behavior depends on the
[`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting and how the function is called.

If the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting *is* defined:

- `get_connection()` with no arguments will return
  [`mailers.default`](#django.core.mail.mailers.default).
- `get_connection(...)` called with only `fail_silently` or other
  keyword arguments will create an instance of
  `MAILERS["default"]` with any keywords added to the
  default mailer's [`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS).
- `get_connection(backend, ...)` with a backend import path will raise
  an error.

If the [`MAILERS`](/ja/6.1/ref/settings/#std-setting-MAILERS) setting is *not* defined:

- `get_connection()` with no arguments will return an instance of the
  email backend specified in [`EMAIL_BACKEND`](/ja/6.1/ref/settings/#std-setting-EMAIL_BACKEND).
- If you specify the `backend` argument, an instance of that backend will
  be instantiated.
- If the keyword argument `fail_silently` is True, certain
  backend-dependent exceptions during the email sending process will be
  silently ignored.
- その他のキーワード引数はメールバックエンドのコンストラクタに直接渡されます。

> **Deprecated since Django 6.0**
>
> バージョン 6.0 で非推奨: Passing `fail_silently` as a positional argument is deprecated.

> **Deprecated since Django 6.1**
>
> バージョン 6.1 で非推奨: `get_connection()` is deprecated and will be removed in Django
> 7.0. Switch to [`mailers[alias]`](#django.core.mail.mailers). See
> [Replacing get\_connection() and connection arguments](/ja/6.1/howto/mailers-migration/#migrating-to-mailers-get-connection) for migration suggestions.

### Email backend API

Instances of an email backend class have the following methods:

- `open()` は、長寿命のメール送信のコネクションをインスタンス化します。
- `close()` は、現在のメール送信のコネクションを閉じます。
- `send_messages(email_messages)` sends a list of [`EmailMessage`](#django.core.mail.EmailMessage)
  objects. If the connection is not open, this call will implicitly open the
  connection, and close the connection afterward. If the connection is already
  open, it will be left open after mail has been sent.

A backend instance can also be used as a context manager, which will
automatically call `open()` and `close()` as needed. An example is in
[Sending many messages efficiently](#topics-sending-multiple-emails).

## 開発用にメールを設定する

Django に電子メールをまったく送信させたくない場合もあるでしょう。たとえば、ウェブサイトの開発中に数千通のメールを送信したくはないでしょう。しかし、適切な条件で適切な人々にメールが送信され、これらのメールが正しい内容を含んでいるか検証したいことがあるかもしれません。

ローカル開発用にメールを設定する最も簡単な方法は [console](#topic-email-console-backend) メールバックエンドを使うことです。このバックエンドはすべてのメールを `stdout` にリダイレクトし、メールの内容を検査できるようにします。

[ファイル](#topic-email-file-backend) メールバックエンドも開発に役立ちます。このバックエンドは全ての SMTP コネクションをファイルにダンプし、都合の良いときに調べられるようにします。

Another approach is to use a mocked SMTP server that receives the emails
locally and displays them to the terminal, but does not actually send
anything. The [aiosmtpd](https://pypi.org/project/aiosmtpd/) package provides a way to accomplish this:

```shell
python -m pip install "aiosmtpd >= 1.4.5"

python -m aiosmtpd -n -l localhost:8025
```

This command will start a minimal SMTP server listening on port 8025 of
localhost. This server prints to standard output all email headers and the
email body. You then only need to set an SMTP backend's `"host"` and
`"port"` [`OPTIONS`](/ja/6.1/ref/settings/#std-setting-MAILERS-OPTIONS) accordingly. For a more
detailed discussion of SMTP server options, see the documentation of the
[aiosmtpd](https://aiosmtpd.readthedocs.io/en/latest/) module.

アプリケーションでのメール送信のユニットテストについては、テストのドキュメントの [メールサービス](/ja/6.1/topics/testing/tools/#topics-testing-email) セクションを参照してください。