For sending large volume of emails you should ensure they are not spam. Spam is mail sent to end users without their consent. It has nothing to do with the content of the mail, it is just a matter of consent. To increase the inbox delivery rate of your messages, make sure that all recipients on your distribution lists actually want to receive the mail
All bulk senders must ensure that their lists are confirmed opt-ins(COI) and offer a method to unsubscribe with every mail
We've listed a few Guidelines for sending large volume of emails below, however please note that we can NOT actually guarantee that your email will be delivered.
Authentication & Identification
To ensure that the recipients can identify you:
- Use a consistent IP address(es) to send bulk mail.
- Keep valid reverse DNS records for the IP address(es) from which you send mail, pointing to your domain.
- Use the same address in the 'From:' header on every bulk mail you send.
We also recommend publishing an SPF record, and signing with DKIM or DomainKeys.
Subscription
Each user on your distribution list should opt to receive messages from you in one of the following ways (opt-in):
- Through an email asking to subscribe to your list.
- By manually checking a box on a web form, or within a piece of software. >
We also recommend that you verify each email address before subscribing them to your list.
The following methods of address collection are not considered 'opt-in' and are not recommended:
- Using an email address list purchased from a third-party.
- Setting a checkbox on a web form or within a piece of software to subscribe all users by default (requiring users to explicitly opt-out of mailings).
Unsubscribing
A user must be able to unsubscribe from your mailing list through one of the following means:
- A prominent link in the body of an email leading users to a page confirming his or her unsubscription (no input from the user, other than confirmation,should be required).
- By replying to your email with an unsubscribe request.
To help ensure that your messages aren't flagged as spam, we also recommend that you:
- Automatically unsubscribe users whose addresses bounce multiple pieces of mail.
- Periodically send confirmation messages to users.
- Include each mailing list they are signed up for, and offer the opportunity to unsubscribe from those in which they are no longer interested.
It's possible that your users forward mail from other accounts, so we recommend that you:
- Explicitly indicate the email address subscribed to your list.
- Support a URL method of unsubscribing from your mailing li st (this is beneficial if your mailing list manager can't tell who is unsubscribing based on the 'Reply-to:' address).
Format
- All bulk messages you send must be formatted according to RFC 2822 SMTP standards and, if using HTML, w3.org standards.
- As per RFC guidelines the the clients Domain should have a postmaster@domain.tld and a abuse@domain.tld mailbox created to accecpt mails. Please refer to link http://www.rfc-ignorant.org/rfcs/rfc2142.php
- Messages should indicate that they are bulk mail, using the 'Precedence: bulk' header field.
- Attempts to hide the true sender of the message or the true landing page for any web links in the message may result in non-delivery.
- The subject of each message should be relevant to the body's content and not be misleading.
- The domain being used to send out mail should have a Privacy Policy
