SendGrid

Anymail integrates with the SendGrid email service, using their Web API v3.

Changed in version 0.8: Earlier Anymail releases used SendGrid’s v2 API. If you are upgrading, please review the porting notes.

Important

Troubleshooting: If your SendGrid messages aren’t being delivered as expected, be sure to look for “drop” events in your SendGrid activity feed.

SendGrid detects certain types of errors only after the send API call appears to succeed, and reports these errors as drop events.

Settings

EMAIL_BACKEND

To use Anymail’s SendGrid backend, set:

EMAIL_BACKEND = "anymail.backends.sendgrid.EmailBackend"

in your settings.py.

SENDGRID_API_KEY

A SendGrid API key with “Mail Send” permission. (Manage API keys in your SendGrid API key settings.) Required.

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

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

SENDGRID_GENERATE_MESSAGE_ID

Whether Anymail should generate a Message-ID for messages sent through SendGrid, to facilitate event tracking.

Default True. You can set to False to disable this behavior. See Message-ID quirks below.

SENDGRID_MERGE_FIELD_FORMAT

If you use merge data, set this to a str.format() formatting string that indicates how merge fields are delimited in your SendGrid templates. For example, if your templates use the -field- hyphen delimiters suggested in some SendGrid docs, you would set:

ANYMAIL = {
    ...
    "SENDGRID_MERGE_FIELD_FORMAT": "-{}-",
}

The placeholder {} will become the merge field name. If you need to include a literal brace character, double it up. (For example, Handlebars-style {{field}} delimiters would take the format string "{{{{{}}}}}".)

The default None requires you include the delimiters directly in your merge_data keys. You can also override this setting for individual messages. See the notes on SendGrid templates and merge below.

SENDGRID_API_URL

The base url for calling the SendGrid API.

The default is SENDGRID_API_URL = "https://api.sendgrid.com/v3/" (It’s unlikely you would need to change this.)

esp_extra support

To use SendGrid features not directly supported by Anymail, you can set a message’s esp_extra to a dict of parameters for SendGrid’s v3 Mail Send API. Your esp_extra dict will be deeply merged into the parameters Anymail has constructed for the send, with esp_extra having precedence in conflicts.

Example:

message.open_tracking = True
message.esp_extra = {
    "asm": {  # SendGrid subscription management
        "group_id": 1,
        "groups_to_display": [1, 2, 3],
    },
    "tracking_settings": {
        "open_tracking": {
            # Anymail will automatically set `"enable": True` here,
            # based on message.open_tracking.
            "substitution_tag": "%%OPEN_TRACKING_PIXEL%%",
        },
    },
}

(You can also set "esp_extra" in Anymail’s global send defaults to apply it to all messages.)

Limitations and quirks

Message-ID

SendGrid does not return any sort of unique id from its send API call. Knowing a sent message’s ID can be important for later queries about the message’s status.

To work around this, Anymail by default generates a new Message-ID for each outgoing message, provides it to SendGrid, and includes it in the anymail_status attribute after you send the message.

In later SendGrid API calls, you can match that Message-ID to SendGrid’s smtp-id event field. (Anymail uses an additional workaround to ensure smtp-id is included in all SendGrid events, even those that aren’t documented to include it.)

Anymail will use the domain of the message’s from_email to generate the Message-ID. (If this isn’t desired, you can supply your own Message-ID in the message’s extra_headers.)

To disable all of these Message-ID workarounds, set ANYMAIL_SENDGRID_GENERATE_MESSAGE_ID to False in your settings.

Single Reply-To

SendGrid’s v3 API only supports a single Reply-To address (and blocks a workaround that was possible with the v2 API).

If your message has multiple reply addresses, you’ll get an AnymailUnsupportedFeature error—or if you’ve enabled ANYMAIL_IGNORE_UNSUPPORTED_FEATURES, Anymail will use only the first one.

Invalid Addresses

SendGrid will accept and send just about anything as a message’s from_email. (And email protocols are actually OK with that.)

(Tested March, 2016)

Batch sending/merge and ESP templates

SendGrid offers both ESP stored templates and batch sending with per-recipient merge data.

You can use a SendGrid stored template by setting a message’s template_id to the template’s unique id. Alternatively, you can refer to merge fields directly in an EmailMessage’s subject and body—the message itself is used as an on-the-fly template.

In either case, supply the merge data values with Anymail’s normalized merge_data and merge_global_data message attributes.

message = EmailMessage(
    ...
    # omit subject and body (or set to None) to use template content
    to=["alice@example.com", "Bob <bob@example.com>"]
)
message.template_id = "5997fcf6-2b9f-484d-acd5-7e9a99f0dc1f"  # SendGrid id
message.merge_data = {
    'alice@example.com': {'name': "Alice", 'order_no': "12345"},
    'bob@example.com': {'name': "Bob", 'order_no': "54321"},
}
message.merge_global_data = {
    'ship_date': "May 15",
}
message.esp_extra = {
    # Tell Anymail this SendGrid template uses "-field-" to refer to merge fields.
    # (We could also just set SENDGRID_MERGE_FIELD_FORMAT in our ANYMAIL settings.)
    'merge_field_format': "-{}-"
}

SendGrid doesn’t have a pre-defined merge field syntax, so you must tell Anymail how substitution fields are delimited in your templates. There are three ways you can do this:

  • Set 'merge_field_format' in the message’s esp_extra to a python str.format() string, as shown in the example above. (This applies only to that particular EmailMessage.)
  • Or set SENDGRID_MERGE_FIELD_FORMAT in your Anymail settings. This is usually the best approach, and will apply to all messages sent through SendGrid. (You can still use esp_extra to override for individual messages.)
  • Or include the field delimiters directly in all your merge_data and merge_global_data keys. E.g.: {'-name-': "Alice", '-order_no-': "12345"}. (This can be error-prone, and difficult to move to other ESPs.)

When you supply per-recipient merge_data, Anymail automatically changes how it communicates the “to” list to SendGrid, so that so that each recipient sees only their own email address. (Anymail creates a separate “personalization” for each recipient in the “to” list; any cc’s or bcc’s will be duplicated for every to-recipient.)

SendGrid templates allow you to mix your EmailMessage’s subject and body with the template subject and body (by using <%subject%> and <%body%> in your SendGrid template definition where you want the message-specific versions to appear). If you don’t want to supply any additional subject or body content from your Django app, set those EmailMessage attributes to empty strings or None.

See the SendGrid’s template overview and transactional template docs for more information.

Status tracking webhooks

If you are using Anymail’s normalized status tracking, enter the url in your SendGrid mail settings, under “Event Notification”:

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

Be sure to check the boxes in the SendGrid settings for the event types you want to receive.

SendGrid will report these Anymail event_types: queued, rejected, bounced, deferred, delivered, opened, clicked, complained, unsubscribed, subscribed.

The event’s esp_event field will be a dict of Sendgrid event fields, for a single event. (Although SendGrid calls webhooks with batches of events, Anymail will invoke your signal receiver separately for each event in the batch.)

Upgrading to SendGrid’s v3 API

Anymail v0.8 switched to SendGrid’s preferred v3 send API. (Earlier Anymail releases used their v2 API.)

For many Anymail projects, this change will be entirely transparent. (Anymail’s whole reason for existence is abstracting ESP APIs, so that your own code doesn’t need to worry about the details.)

There are three cases where SendGrid has changed features that would require updates to your code:

  1. If you are using SendGrid’s username/password auth (your settings include SENDGRID_USERNAME and SENDGRID_PASSWORD), you must switch to an API key. See SENDGRID_API_KEY.

    (If you are already using a SendGrid API key with v2, it should work just fine with v3.)

  2. If you are using Anymail’s esp_extra attribute to supply API-specific parameters, the format has changed.

    Search your code for “esp_extra” (e.g., git grep esp_extra) to determine whether this affects you. (Anymail’s "merge_field_format" is unchanged, so if that’s the only thing you have in esp_extra, no changes are needed.)

    The new API format is considerably simpler and more logical. See esp_extra support below for examples of the new format and a link to relevant SendGrid docs.

    Anymail will raise an error if it detects an attempt to use the v2-only "x-smtpapi" settings in esp_extra when sending.

  3. If you send messages with multiple Reply-To addresses, SendGrid no longer supports this. (Multiple reply emails in a single message are not common.)

    Anymail will raise an error if you attempt to send a message with multiple Reply-To emails. (You can suppress the error with ANYMAIL_IGNORE_UNSUPPORTED_FEATURES, which will ignore all but the first reply address.)

As an alternative, Anymail (for the time being) still includes a copy of the SendGrid v2 backend. See Legacy v2 API support below if you’d prefer to stay on the older SendGrid API.

Legacy v2 API support

Changed in version 0.8.

Anymail v0.8 switched to SendGrid’s v3 Web API in its primary SendGrid email backend. SendGrid encourages all users to migrate to their v3 API.

For Anymail users who still need it, a legacy backend that calls SendGrid’s earlier Web API v2 Mail Send remains available. Be aware that v2 support is considered deprecated and may be removed in a future Anymail release.

To use Anymail’s SendGrid v2 backend, edit your settings.py:

EMAIL_BACKEND = "anymail.backends.sendgrid_v2.EmailBackend"
ANYMAIL = {
    "SENDGRID_API_KEY": "<your API key>",
}

The same SENDGRID_API_KEY will work with either Anymail’s v2 or v3 SendGrid backend.

Nearly all of the documentation above for Anymail’s v3 SendGrid backend also applies to the v2 backend, with the following changes:

Username/password auth (SendGrid v2 only)

SendGrid v2 allows a username/password instead of an API key (though SendGrid encourages API keys for all new installations). If you must use username/password auth, set:

EMAIL_BACKEND = "anymail.backends.sendgrid_v2.EmailBackend"
ANYMAIL = {
    "SENDGRID_USERNAME": "<sendgrid credential with Mail permission>",
    "SENDGRID_PASSWORD": "<password for that credential>",
    # And leave out "SENDGRID_API_KEY"
}

This is not the username/password that you use to log into SendGrid’s dashboard. Create credentials specifically for sending mail in the SendGrid credentials settings.

Either username/password or SENDGRID_API_KEY are required (but not both).

Anymail will also look for SENDGRID_USERNAME and SENDGRID_PASSWORD at the root of the settings file if neither ANYMAIL["SENDGRID_USERNAME"] nor ANYMAIL_SENDGRID_USERNAME is set.

Duplicate attachment filenames (SendGrid v2 limitation)

Anymail is not capable of communicating multiple attachments with the same filename to the SendGrid v2 API. (This also applies to multiple attachments with no filename, though not to inline images.)

If you are sending multiple attachments on a single message, make sure each one has a unique, non-empty filename.

Message bodies with ESP templates (SendGrid v2 quirk)

Anymail’s SendGrid v2 backend will convert empty text and HTML bodies to single spaces whenever template_id is set, to ensure the plaintext and HTML from your template are present in your outgoing email. This works around a limitation in SendGrid’s template rendering.

Multiple Reply-To addresses (SendGrid v2 only)

Unlike SendGrid’s v3 API, Anymail is able to support multiple Reply-To addresses with their v2 API.

esp_extra with SendGrid v2

Anymail’s esp_extra attribute is merged directly with the API parameters, so the format varies between SendGrid’s v2 and v3 APIs. With the v2 API, most interesting settings appear beneath 'x-smtpapi'. Example:

message.esp_extra = {
    'x-smtpapi': {  # for SendGrid v2 API
        "asm_group": 1,  # Assign SendGrid unsubscribe group for this message
        "asm_groups_to_display": [1, 2, 3],
        "filters": {
            "subscriptiontrack": {  # Insert SendGrid subscription management links
                "settings": {
                    "text/html": "If you would like to unsubscribe <% click here %>.",
                    "text/plain": "If you would like to unsubscribe click here: <% %>.",
                    "enable": 1
                }
            }
        }
    }
}

The value of esp_extra should be a dict of parameters for SendGrid’s v2 mail.send API. Any keys in the dict will override Anymail’s normal values for that parameter, except that 'x-smtpapi' will be merged.