The guidelines delineated in this article will help you successfully dispatch and deliver emails in large numbers (5,000 or more) to personal email accounts.

Recommended sending practices

Before we specify the guidelines to frequently dispatch large amounts of emails, we recommend that you peruse certain general best practices to follow while mailing messages.

1. Use email authentication protocols such as SPF, DKIM, and DMARC to validate sender domain authenticity.
2. In principle, send all messages from the same IP address. In case you must send mails from multiple IP addresses, use a different IP address for each type of message. For instance, use one IP address for sending account notifications and a distinct IP address for sending promotional messages.
3. Messages of the same category should have the same From: email address. For example, messages from a domain called notifyvisitors.com might have From: addresses like:

• Sales receipt messages: [email protected]
• Promotional messages: [email protected]
• Account notification messages: [email protected]

Guidelines for safely increasing the sending volume

Increasing the sending volume too quickly, in an unmonitored manner can tarnish the sender domain’s reputation and can result in delivery problems such as messages getting directed to spam or emails getting blocked by servers.

If you intend to dispatch large amounts of emails regularly yet avoid delivery issues caused by increasing the sending volume, we recommend you to follow the undermentioned guidelines:

Do’s

1. Send mails at a consistent rate.
2. Begin with a low sending volume to engaged users, then slowly and steadily increase the volume over time.
3. As you continue to increase the sending volume, periodically monitor server responses, spam rate, and the sending domain's reputation.

Regular monitoring will enable you to quickly adapt in case your sending is rate limited, if the spam rate increases, or when the sending domain's reputation drops.

Click here to learn more about maintaining and mastering the sending domain’s reputation.

4. If you alter or change the format of bulk emails, then make sure that you increase the traffic segment with the new format gradually.
5. In case you make significant changes to the sending infrastructure, email or email header structure, then separately, steadily and incrementally populate the modified traffic segment.
6. If messages start bouncing or start being deferred, reduce the sending volume until the SMTP error rate decreases. Then, increase again gradually. In case bounces and deferrals continue at a low volume, review individual messages to identify problems. For example, you can try sending a blank test message and check whether it encounters issues.

Don’ts

1. Avoid sending emails in bursts.
2. Avoid introducing abrupt spikes in the sending volume, especially if you do not have a history of dispatching mails in large amounts. For instance, doubling previously sent volumes all of a sudden, could potentially result in rate limiting or reputation drops.
3. Don't blend or mix different types of content within the same message. For instance, don't include promotions in order confirmation or sales receipt messages.
4. Don't impersonate other domains or senders without prior permission. This practice is called spoofing, and email service providers may mark messages from such domains as spam.
5. Don't mark internal messages as spam. This can negatively impact your domain's reputation, and future messages might be marked as spam.
6. Don't purchase email addresses from other companies (unauthorized vendors).
7. Don't dispatch messages to people who didn't sign up or subscribe to receive messages from your brand. Such recipients might mark your messages as spam, and future messages to these recipients will be marked as spam.
8. Avoid opt-in forms that automatically subscribe users. Some countries and regions restrict automatic opt-ins. Before you opt-in users automatically, check the laws in your geographical region.

The undermentioned factors affect the rate at which you can increase the sending volume:

• Amount of email sent:
• The more emails you send, the more slowly you should increase the sending volume.
• Frequency of sending emails:
• You can increase the sending volume more quickly if you send daily instead of weekly.
• Recipient feedback about your messages:
• Make sure that you send messages only to those people who subscribe to your emails, and always provide recipients with an option to unsubscribe.

Adhering to the best practices and recommendations delineated above, will in all likelihood, automatically resolve most deliverability issues encountered in the event of a spike in email activity.