Deliverability Introduction

Email deliverability refers to the rate at which your emails are successfully delivered to your recipients’ inboxes without negatively impacting your sending reputation with your recipients’ inbox providers. Below is a quick-start guide to email deliverability listing several tips to improve and maintain your sender reputation.

Best Practices

When it comes to deliverability, there is a long list of best practices that you should follow when creating email content, and managing your email programs. Following are several articles that discuss many of these best practices including engagement, email content, IP warm-up, email notifications, and deliverability in general.


In addition to deliverability best-practices, there are certain requirements that must be met in order to remain compliant with SendGrid’s Terms of Service and the legal requirements laid out in the CAN-SPAM act and other relevant legislation.

List Management

Collecting a list of interested and engaged recipients is the first step that you should take to ensure the delivery of your email, and to keep your recipients from reporting your emails as spam. For more information about list management, see our documentation. .


Spam is simply defined as unwanted email. Your emails might be sent to the spam folder, or marked as spam by your recipients because you are sending to the wrong people, or because your content is caught by spam filters. Here are several articles discussing spam, and what to do if your emails are marked as such.


A suppression is an email that fails to deliver or is actively prevented from being delivered. There are a variety of suppressions: some are wanted, while others are a result of poor deliverability practices. Following is a list of common suppressions, along with information on how to handle these different events.


A bounce is simply a message that is returned to the original sending server. There can be permanent and temporary bounces.


A drop occurs when SendGrid identifies a message that has been added to a suppression list. Bounces, unsubscribes, spam reports, and invalid email addresses all result in a drop.


An unsubscribe occurs when one of your recipients requests to no longer receive one or more of your emails. There are group unsubscribes, where a recipient unsubscribes from a subset of your email, and global unsubscribes, where a recipient requests to be removed from all of your emails.

Sender authentication

Sender authentication is one of the most critical aspects of maintaining your sender reputation. For a complete discussion of sender authentication, along with a list of all of our sender authentication documentation, please see the reference linked below.