Mailgun

Anymail integrates with the Sinch Mailgun transactional email service, using their messages REST API.

Note

By default, Anymail connects to Mailgun’s US-based API servers. If you are using Mailgun’s EU region, be sure to change the MAILGUN_API_URL Anymail setting as shown below.

Settings

EMAIL_BACKEND

To use Anymail’s Mailgun backend, set:

EMAIL_BACKEND = "anymail.backends.mailgun.EmailBackend"

in your settings.py.

MAILGUN_API_KEY

Required for sending:

ANYMAIL = {
    ...
    "MAILGUN_API_KEY": "<your API key>",
}

The key can be either:

(recommended) a domain-level Mailgun “Sending API key,” found in Mailgun’s dashboard under “Sending” > “Domain settings” > “Sending API keys” (make sure the correct domain is selected in the popup at top right!)
an account-level “Mailgun API key” from your Mailgun API security settings.

The account-level API key permits sending from any verified domain, but it also allows access to all other Mailgun APIs for your account (which Anymail doesn’t need).

The domain-level sending API key is preferred if you send from only a single domain. With multiple domains, either use an account API key, or supply the sending API key for a default domain in settings.py and use Django’s get_connection() to substitute a different sending API key for other domains:

from django.core.mail import EmailMessage, get_connection
# By default, use the settings.py MAILGUN_API_KEY:
message1 = EmailMessage(from_email="[email protected]", ...)
message1.send()

# Use a different sending API key for this message:
connection = get_connection(api_key=SENDING_API_KEY_FOR_OTHER_DOMAIN)
message2 = EmailMessage(from_email="[email protected]", ...,
                        connection=connection)
message2.send()

Anymail will also look for MAILGUN_API_KEY at the root of the settings file if neither ANYMAIL["MAILGUN_API_KEY"] nor ANYMAIL_MAILGUN_API_KEY is set.

MAILGUN_API_URL

The base url for calling the Mailgun API.

The default is MAILGUN_API_URL = "https://api.mailgun.net/v3", which connects to Mailgun’s US service. You must change this if you are using Mailgun’s European region:

ANYMAIL = {
  "MAILGUN_API_KEY": "...",
  "MAILGUN_API_URL": "https://api.eu.mailgun.net/v3",
  # ...
}

(Do not include your sender domain or “/messages” in the API URL. Anymail figures this out for you.)

MAILGUN_SENDER_DOMAIN

If you are using a specific Mailgun sender domain that is different from your messages’ from_email domains, set this to the domain you’ve configured in your Mailgun account.

If your messages’ from_email domains always match a configured Mailgun sender domain, this setting is not needed.

See Email sender domain below for examples.

MAILGUN_WEBHOOK_SIGNING_KEY

Added in version 6.1.

Required for tracking or inbound webhooks. Your “HTTP webhook signing key” from the Mailgun API security settings:

ANYMAIL = {
    ...
    "MAILGUN_WEBHOOK_SIGNING_KEY": "<your webhook signing key>",
}

If not provided, Anymail will attempt to validate webhooks using the MAILGUN_API_KEY setting instead. (These two keys have the same values for new Mailgun users, but will diverge if you ever rotate either key.)

Email sender domain

Mailgun’s API requires identifying the sender domain. By default, Anymail uses the domain of each message’s from_email (e.g., “example.com” for “from@example.com”).

You will need to override this default if you are using a dedicated Mailgun sender domain that is different from a message’s from_email domain.

For example, if you are sending from “orders@example.com”, but your Mailgun account is configured for “mail1.example.com”, you should provide MAILGUN_SENDER_DOMAIN in your settings.py:

ANYMAIL = {
    ...
    "MAILGUN_API_KEY": "<your API key>",
    "MAILGUN_SENDER_DOMAIN": "mail1.example.com"
}

If you need to override the sender domain for an individual message, use Anymail’s envelope_sender (only the domain is used; anything before the @ is ignored):

message = EmailMessage(from_email="[email protected]", ...)
message.envelope_sender = "[email protected]"  # the "anything@" is ignored

exp_extra support

Anymail’s Mailgun backend will pass all esp_extra values directly to Mailgun. You can use any of the (non-file) parameters listed in the Mailgun sending docs. Example:

message = AnymailMessage(...)
message.esp_extra = {
    'o:deliverytime-optimize-period': '24h',  # use Mailgun Send Time Optimization
    'o:time-zone-localize': '16:00',  # use Mailgun Timezone Optimization
    'o:testmode': 'yes',  # use Mailgun's test mode
}

Limitations and quirks

Attachments require filenames

Mailgun has an undocumented API requirement that every attachment must have a filename. Attachments with missing filenames are silently dropped from the sent message. Similarly, every inline attachment must have a Content-ID.

To avoid unexpected behavior, Anymail will raise an AnymailUnsupportedFeature error if you attempt to send a message through Mailgun with any attachments that don’t have filenames (or inline attachments that don’t have Content-IDs).

Ensure your attachments have filenames by using message.attach_file(filename), message.attach(content, filename="..."), or if you are constructing your own MIME objects to attach, mimeobj.add_header("Content-Disposition", "attachment", filename="...").

Ensure your inline attachments have Content-IDs by using Anymail’s inline image helpers, or if you are constructing your own MIME objects, mimeobj.add_header("Content-ID", "...") and mimeobj.add_header("Content-Disposition", "inline").

Changed in version 4.3: Earlier Anymail releases did not check for these cases, and attachments without filenames/Content-IDs would be ignored by Mailgun without notice.

Display name problems with punctuation and non-ASCII characters

Mailgun does not correctly handle certain display names in From, To, and other email headers. If a display name includes both non-ASCII characters and certain punctuation (such as parentheses), the resulting email will use a non-standard encoding that causes some email clients to display additional " or \" characters wrapping the display name. (Verified and reported to Mailgun engineering 3/2022. See Anymail issue #270 for examples and specific details.)

Envelope sender uses only domain

Anymail’s envelope_sender is used to select your Mailgun sender domain. For obvious reasons, only the domain portion applies. You can use anything before the @, and it will be ignored.

Using merge_metadata and merge_headers with merge_data

If you use both Anymail’s merge_data and merge_metadata features, make sure your merge_data keys do not start with v:.

Similarly, if you use Anymail’s merge_headers together with merge_data, make sure your merge_data keys do not start with h:.

(It’s a good idea anyway to avoid colons and other special characters in merge data keys, as this isn’t generally portable to other ESPs.)

The same underlying Mailgun feature (“recipient-variables”) is used to implement all three Anymail features. To avoid conflicts, Anymail prepends v: to recipient variables needed for merge metadata, and h: for merge headers recipient variables. (These prefixes are stripped as Mailgun prepares the message to send, so won’t appear in your Mailgun API logs or the metadata that is sent to tracking webhooks.)

Additional limitations on merge_data with template_id

If you are using Mailgun’s stored handlebars templates (Anymail’s template_id), merge_data cannot contain complex types or have any keys that conflict with metadata. See Limitations with stored handlebars templates below for more details.

merge_metadata values default to empty string

If you use Anymail’s merge_metadata feature, and you supply metadata keys for some recipients but not others, Anymail will first try to resolve the missing keys in metadata, and if they are not found there will default them to an empty string value.

Your tracking webhooks will receive metadata values (either that you provided or the default empty string) for every key used with any recipient in the send.

AMP for Email

Mailgun supports sending AMPHTML email content. To include it, use message.attach_alternative("...AMPHTML content...", "text/x-amp-html") (and be sure to also include regular HTML and/or text bodies, too).

Added in version 8.2.

Batch sending/merge and ESP templates

Mailgun supports ESP stored templates, on-the-fly templating, and batch sending with per-recipient merge data.

Changed in version 7.0: Added support for Mailgun’s stored (handlebars) templates.

Mailgun has two different syntaxes for substituting data into templates:

“Recipient variables” look like %recipient.name%, and are used with on-the-fly templates. You can refer to a recipient variable inside a message’s body, subject, or other message attributes defined in your Django code. See Mailgun batch sending for more information. (Note that Mailgun’s docs also sometimes refer to recipient variables as “template variables,” and there are some additional predefined ones described in their docs.)
“Template substitutions” look like {{ name }}, and can only be used in handlebars templates that are defined and stored in your Mailgun account (via the Mailgun dashboard or API). You refer to a stored template using Anymail’s template_id in your Django code. See Mailgun templates for more information.

With either type of template, you supply the substitution data using Anymail’s normalized merge_data and merge_global_data message attributes. Anymail will figure out the correct Mailgun API parameters to use.

Here’s an example defining an on-the-fly template that uses Mailgun recipient variables:

message = EmailMessage(
    from_email="[email protected]",
    # Use %recipient.___% syntax in subject and body:
    subject="Your order %recipient.order_no% has shipped",
    body="""Hi %recipient.name%,
            We shipped your order %recipient.order_no%
            on %recipient.ship_date%.""",
    to=["[email protected]", "Bob <[email protected]>"]
)
# (you'd probably also set a similar html body with %recipient.___% variables)
message.merge_data = {
    '[email protected]': {'name': "Alice", 'order_no': "12345"},
    '[email protected]': {'name': "Bob", 'order_no': "54321"},
}
message.merge_global_data = {
    'ship_date': "May 15"  # Anymail maps globals to all recipients
}

And here’s an example that uses the same data with a stored template, which could refer to {{ name }}, {{ order_no }}, and {{ ship_date }} in its definition:

message = EmailMessage(
    from_email="[email protected]",
    # The message body and html_body come from from the stored template.
    # (You can still use %recipient.___% fields in the subject:)
    subject="Your order %recipient.order_no% has shipped",
    to=["[email protected]", "Bob <[email protected]>"]
)
message.template_id = 'shipping-notification'  # name of template in our account
# The substitution data is exactly the same as in the previous example:
message.merge_data = {
    '[email protected]': {'name': "Alice", 'order_no': "12345"},
    '[email protected]': {'name': "Bob", 'order_no': "54321"},
}
message.merge_global_data = {
    'ship_date': "May 15"  # Anymail maps globals to all recipients
}

When you supply per-recipient merge_data, Anymail supplies Mailgun’s recipient-variables parameter, which puts Mailgun in batch sending mode so that each “to” recipient sees only their own email address. (Any cc’s or bcc’s will be duplicated for every to-recipient.)

If you want to use batch sending with a regular message (without a template), set merge data to an empty dict: message.merge_data = {}.

Mailgun does not natively support global merge data. Anymail emulates the capability by copying any merge_global_data values to every recipient.

Limitations with stored handlebars templates

Although Anymail tries to insulate you from Mailgun’s relatively complicated API parameters for template substitutions in batch sends, there are two cases it can’t handle. These only apply to stored handlebars templates (when you’ve set Anymail’s template_id attribute).

First, metadata and template merge data substitutions use the same underlying “custom data” API parameters when a handlebars template is used. If you have any duplicate keys between your tracking metadata (metadata/merge_metadata) and your template merge data (merge_data/merge_global_data), Anymail will raise an AnymailUnsupportedFeature error.

Second, Mailgun’s API does not allow complex data types like lists or dicts to be passed as template substitutions for a batch send (confirmed with Mailgun support 8/2019). Your Anymail merge_data and merge_global_data should only use simple types like string or number. This means you cannot use the handlebars {{#each item}} block helper or dotted field notation like {{object.field}} with data passed through Anymail’s normalized merge data attributes.

Most ESPs do not support complex merge data types, so trying to do that is not recommended anyway, for portability reasons. But if you do want to pass complex types to Mailgun handlebars templates, and you’re only sending to one recipient at a time, here’s a (non-portable!) workaround:

# Using complex substitutions with Mailgun handlebars templates.
# This works only for a single recipient, and is not at all portable between ESPs.
message = EmailMessage(
    from_email="[email protected]",
    to=["[email protected]"],  # single recipient *only* (no batch send)
    subject="Your order has shipped",  # recipient variables *not* available
)
message.template_id = 'shipping-notification'  # name of template in our account
substitutions = {
    'items': [  # complex substitution data
        {'product': "Anvil", 'quantity': 1},
        {'product': "Tacks", 'quantity': 100},
    ],
    'ship_date': "May 15",
}
# Do *not* set Anymail's message.merge_data, merge_global_data, or merge_metadata.
# Instead add Mailgun custom variables directly:
message.extra_headers['X-Mailgun-Variables'] = json.dumps(substitutions)

Status tracking webhooks

Changed in version 4.0: Added support for Mailgun’s June, 2018 (non-“legacy”) webhook format.

Changed in version 6.1: Added support for a new MAILGUN_WEBHOOK_SIGNING_KEY setting, separate from your MAILGUN_API_KEY.

If you are using Anymail’s normalized status tracking, enter the url in the Mailgun webhooks config for your domain. (Be sure to select the correct sending domain—Mailgun’s sandbox and production domains have separate webhook settings.)

Mailgun allows you to enter a different URL for each event type: just enter this same Anymail tracking URL for all events you want to receive:

https://random:random@yoursite.example.com/anymail/mailgun/tracking/

random:random is an ANYMAIL_WEBHOOK_SECRET shared secret

yoursite.example.com is your Django site

Mailgun implements a limited form of webhook signing, and Anymail will verify these signatures against your MAILGUN_WEBHOOK_SIGNING_KEY Anymail setting. By default, Mailgun’s webhook signature provides similar security to Anymail’s shared webhook secret, so it’s acceptable to omit the ANYMAIL_WEBHOOK_SECRET setting (and “{random}:{random}@” portion of the webhook url) with Mailgun webhooks.

Mailgun will report these Anymail event_types: delivered, rejected, bounced, complained, unsubscribed, opened, clicked.

The event’s esp_event field will be the parsed Mailgun webhook payload as a Python dict with "signature" and "event-data" keys.

Anymail uses Mailgun’s webhook token as its normalized event_id, rather than Mailgun’s event-data id (which is only guaranteed to be unique during a single day). If you need the event-data id, it can be accessed in your webhook handler as event.esp_event["event-data"]["id"]. (This can be helpful for working with Mailgun’s other event APIs.)

Note

Mailgun legacy webhooks

In late June, 2018, Mailgun introduced a new set of webhooks with an improved payload design, and at the same time renamed their original webhooks to “Legacy Webhooks.”

Anymail v4.0 and later supports both new and legacy Mailgun webhooks, and the same Anymail webhook url works as either. Earlier Anymail versions can only be used as legacy webhook urls.

The new (non-legacy) webhooks are preferred, particularly with Anymail’s metadata and tags features. But if you have already configured the legacy webhooks, there is no need to change.

If you are using Mailgun’s legacy webhooks:

The event.esp_event field will be a Django QueryDict of Mailgun event fields (the raw POST data provided by legacy webhooks).
You should avoid using “body-plain,” “h,” “message-headers,” “message-id” or “tag” as metadata keys. A design limitation in Mailgun’s legacy webhooks prevents Anymail from reliably retrieving this metadata from opened, clicked, and unsubscribed events. (This is not an issue with the newer, non-legacy webhooks.)

Inbound webhook

If you want to receive email from Mailgun through Anymail’s normalized inbound handling, follow Mailgun’s Receiving, Forwarding and Storing Messages guide to set up an inbound route that forwards to Anymail’s inbound webhook. Create an inbound route in Mailgun’s dashboard on the Email Receiving panel, or use Mailgun’s API.

Use this url as the route’s “forward” destination:

https://random:random@yoursite.example.com/anymail/mailgun/inbound_mime/

random:random is an ANYMAIL_WEBHOOK_SECRET shared secret

yoursite.example.com is your Django site

mime at the end tells Mailgun to supply the entire message in “raw MIME” format (see note below)

You must use Mailgun’s “forward” route action; Anymail does not currently support “store and notify.” (For debugging, you might find it helpful to also enable the “store” route action to keep a copy of inbound messages on Mailgun’s servers, but Anymail’s inbound webhook won’t work as a store-notify url.)

If you want to use Anymail’s normalized spam_detected and spam_score attributes, you’ll need to set your Mailgun domain’s inbound spam filter to “Deliver spam, but add X-Mailgun-SFlag and X-Mailgun-SScore headers” (in the Mailgun domains config).

Anymail will verify Mailgun inbound message events using your MAILGUN_WEBHOOK_SIGNING_KEY Anymail setting. By default, Mailgun’s webhook signature provides similar security to Anymail’s shared webhook secret, so it’s acceptable to omit the ANYMAIL_WEBHOOK_SECRET setting (and random:random@ portion of the forwarding url) with Mailgun inbound routing.

Note

Anymail supports both of Mailgun’s “fully-parsed” and “raw MIME” inbound message formats. The raw MIME version is preferred to get the most accurate representation of any received email. Using raw MIME also avoids a limitation in Django’s multipart/form-data handling that can strip attachments with certain filenames (and inline images without filenames).

To use raw MIME (recommended), the route forwarding url should end with …/inbound_mime/ as shown above.
To use fully-parsed format (not recommended), omit the _mime so the route forwarding url ends with just …/inbound/.

Changed in version 8.6: Using Mailgun’s fully-parsed inbound message format is no longer recommended.