Help ensure your emails
hit the inbox
Stop guessing why your messages end up in spam. Follow this 26-point checklist to achieve technical compliance, enhanced sender reputation, and delivery success.
Deliverability is the ability to ensure that a very high percentage of the emails you send are not only accepted by receiving servers but also placed directly into the inbox rather than rejected or filtered into spam. Achieving strong deliverability is essential for maximizing the impact of your email program.
Unfortunately, many senders struggle because their emails are either blocked outright or relegated to junk folders. This often happens when they overlook technical requirements, neglect sender reputation, or adopt mailing practices that trigger filtering systems.
To succeed, you must consistently meet both technical standards and reputation benchmarks. That means implementing proper authentication protocols, maintaining a trustworthy sending history, and aligning your practices with recipient expectations.
Here are the key areas to consider so you can meet current sender authentication requirements, protect your reputation, and achieve consistently high delivery rates:
List Maintenance
#1
Purchased Lists
The use of purchased or third-party mailing lists presents substantial legal, operational, and reputational risks for any organization engaging in email communications. Recipients on such lists have typically not provided... [more]
List Maintenance
#2
Adding Recipients
Organizations should only send email communications to individuals who have explicitly requested and consented to receive them. All subscription mechanisms should be designed to ensure that recipients both understand what... [more]
List Maintenance
#3
List Quality
Maintaining a high-quality, up-to-date mailing list is essential for ensuring regulatory compliance, protecting sender reputation, and maximizing the effectiveness of email communications. Organizations should actively manage subscriber engagement and avoid... [more]
Authentication
#4
Use Own Domain
You should always send email from your own domain rather than a free address, as it looks more professional, builds trust, and gives you full control over authentication and reputation.... [more]
Authentication
#5
rDNS / PTR / HELO
The sending IP address must have correctly configured forward and reverse DNS, with a valid fully qualified domain name (FQDN). The hostname presented in the SMTP HELO / EHLO command... [more]
Authentication
#6
SSL / TLS
All outbound email systems must be configured to support current, industry-standard Transport Layer Security (TLS) protocols when communicating with external mail servers. Secure transmission is a fundamental requirement for protecting... [more]
Authentication
#7
SPF
Sender Policy Framework (SPF) is an email authentication mechanism that enables domain owners to specify which IP addresses, hosts, and third-party services are authorized to send email on their behalf.... [more]
Authentication
#8
DKIM
DomainKeys Identified Mail (DKIM) is an email authentication mechanism that uses cryptographic signatures to verify that outbound messages are legitimately associated with the sending domain and have not been altered... [more]
Authentication
#9
DMARC
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication and policy framework that builds upon the results of SPF and DKIM validation. It enables domain owners to define... [more]
Authentication
#10
Dedicated IP
Sending your emails from a dedicated, static IP address is generally recommended once you reach volumes of 50,000 messages per month or more. A dedicated IP allows you to build... [more]
Strategy
#11
One Email Per Recipient
All mailing list communications must be delivered as individual messages to each recipient. Bulk messages addressed to multiple recipients using the “To:”, “Cc:”, or “Bcc:” fields must not be used... [more]
Strategy
#12
Avoid 'No Reply' Addresses
Organizations should avoid the use of “no-reply@” or equivalent non-responsive sender addresses for outbound email communications. All messages should originate from a valid, monitored mailbox that is capable of receiving... [more]
Strategy
#13
ESP
Organizations are strongly advised to use a reputable, dedicated Email Service Provider (ESP) rather than transmitting outbound mail directly from local, on-premises, or unmanaged internet-connected servers. Purpose-built ESP platforms are... [more]
Strategy
#14
Send Consistently
Mailbox providers and filtering systems strongly favor predictable, stable sending patterns over irregular or highly variable transmission volumes. Consistency in email traffic is a key indicator of legitimate, well-managed communication... [more]
Strategy
#15
Avoid Domain-Based Sorting
When distributing messages to mailing lists, recipients should not be grouped or batched based on their email domain (for example, clustering all @gmail.com, @yahoo.com, or @outlook.com addresses together). Domain-based sorting... [more]
Strategy
#16
Safe Sender
Organizations should maintain a consistent and recognizable sender identity for all outbound email communications. Messages should be sent from the same domain and address that recipients originally subscribed to and... [more]
Strategy
#17
Out of Control
Organizations should recognize that ultimate message placement is determined by recipient mailbox providers and end-user filtering systems, which apply proprietary and continuously evolving criteria. These systems may classify messages as... [more]
Monitoring
#18
Bounces
All delivery failure notifications (“bounces”) must be monitored, classified, and managed systematically as part of ongoing list hygiene and deliverability governance. Bounce handling provides critical insight into list quality, infrastructure... [more]
Monitoring
#19
SPAM Complaints
All spam complaints must be treated as high-priority compliance and deliverability incidents. When a recipient marks a message as spam, it generates a strong negative signal to mailbox providers and... [more]
Monitoring
#20
Feedback Data
Organizations should actively monitor sender reputation, delivery performance, and authentication status using established mailbox provider reporting services. Enrolment in platforms such as Microsoft Smart Network Data Services (SNDS) and Google... [more]
Monitoring
#21
Monitor
Organizations should maintain active test accounts with major mailbox providers, including Microsoft and Google, to support continuous monitoring of inbox placement, filtering behaviour, and message presentation. These accounts provide a... [more]
Content
#22
Engagement
Organizations should actively encourage genuine and sustained engagement from recipients as a core component of responsible email communication. Modern mailbox providers continuously evaluate how recipients interact with messages, including whether... [more]
Content
#23
Content
All outbound email content should be developed in accordance with professional communication, accessibility, and deliverability best practices. Message composition plays a significant role in how mailbox providers and recipients evaluate... [more]
Content
#24
Personalize
Organizations should personalize email communications wherever feasible rather than sending identical messages to all recipients. Even modest levels of personalization — such as addressing recipients by name, referencing previous interactions,... [more]
Content
#25
Include Address / Contact Information
All outbound email communications must clearly identify the sending organization and provide accessible contact information. Transparent sender identification is a core requirement of email regulations in many jurisdictions and is... [more]
Content
#26
Unsubscribe
All outbound email communications must include a clear, visible, and easy-to-use unsubscribe mechanism. Recipients must be able to opt out of future communications quickly and without unnecessary barriers. The unsubscribe... [more]