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:
Purchased Lists
The use of purchased mailing lists presents significant compliance and reputational risks. Addresses included may not reflect valid opt-in consent, and in some cases may have been harvested from websites... [more]
Adding Recipients
You should only email individuals who have explicitly opted in and expect to hear from you. Always use a confirmed (double) opt-in process: Send a single confirmation email and require... [more]
List Quality
Emailing recipients after extended periods of inactivity should be approached with caution. Best practice dictates consistent engagement, as subscribers who have not been contacted within 6–12 months may fail to... [more]
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]
rDNS / PTR / HELO
The DNS configuration and HELO / EHLO banner of the sending IP address must be valid and accurate. Invalid or mismatched hostnames may result in message rejection or increased filtering.... [more]
SSL / TLS
Sending servers are required to support current TLS protocols. Non-compliance may result in rejection or negative scoring by recipient systems. Proper TLS configuration not only safeguards message integrity and confidentiality... [more]
SPF
Sender Policy Framework (SPF) defines the authorized IP addresses, hosts, and services permitted to send email for a given domain. Each sending domain must have an accurate SPF record published... [more]
DKIM
DomainKeys Identified Mail (DKIM) provides cryptographic authentication by attaching a digital signature to each outbound message, verifying that it is authorized for the sending domain. A properly implemented DKIM record... [more]
DMARC
Domain-based Message Authentication, Reporting and Conformance (DMARC) is a DNS policy record that leverages SPF and DKIM authentication results. It enables domain owners to define how unauthenticated messages should be... [more]
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 lets you build and... [more]
One Email Per Recipient
When sending to a mailing list, each recipient should receive their own individual email. Do not send single messages with a large number of recipients on the 'To:', 'Cc:', or... [more]
Avoid 'No Reply' Addresses
Using a no-reply@ sender address can reduce email success and harm your reputation. Weaker Deliverability — Positive engagement helps maintain sender reputation. A no-reply address prevents this interaction and may... [more]
ESP
The use of a dedicated Email Service Provider (ESP) is strongly recommended in preference to transmitting directly from a local internet-connected server. ESPs typically ensure compliance with DNS, IP reputation,... [more]
Send Consistently
Mailbox providers generally favor consistent traffic patterns over irregular, high-volume bursts. Concentrating transmission activity into one or two days per month may trigger anomaly detection systems, which can interpret such... [more]
Avoid Domain-Based Sorting
With mailing lists, avoid sorting or batching recipients by email domain (for example, grouping all @gmail.com or @yahoo.com addresses together). Sending large numbers of messages to the same mailbox provider... [more]
Safe Sender
To help recipients recognize your messages, always send from the same domain they originally signed up with. Consistency builds trust and reduces the chance of your emails being mistaken for... [more]
Out of Control
It is important to recognize that recipients and their Internet Service Providers (ISPs) may implement proprietary filtering criteria. Certain systems may classify any message not explicitly whitelisted by the recipient... [more]
Bounces
When an email generates a failure notice (bounce), it’s important to determine whether the cause is hard (permanent) or soft (temporary). Hard bounces (for example, non-existent addresses) indicate permanent delivery... [more]
SPAM Complaints
If a spam complaint is received, you should immediately cease sending any further messages to the affected recipient. Investigate the cause of the complaint and, if it appears to be... [more]
Feedback Data
Enrolment in reputation monitoring services, including Microsoft Smart Network Data Services (SNDS) and Google Postmaster Tools, is recommended to track domain and IP performance. These services provide reporting on reputation,... [more]
Monitor
Sign up for accounts with major providers like Microsoft and Google so you can test whether your emails are reaching the inbox rather than the spam folder. Regularly sending test... [more]
Engagement
Encourage genuine engagement from your recipients. Modern email systems often track whether recipients open, read, or click within messages. If your emails are consistently ignored, deleted quickly, or marked as... [more]
Content
Avoid using spammy content in your subject lines, such as excessive punctuation (!!!) or writing in ALL CAPS, as these can trigger filters or discourage recipients from opening your email.... [more]
Personalize
Rather than sending the exact same email to every recipient, personalize the content where possible. Even small changes, such as addressing the recipient by name, referencing their past interactions, or... [more]
Include Address / Contact Information
Many email regulations require clear sender identification, often including a valid physical mailing address. CAN-SPAM Act (USA): Mandates inclusion of a valid physical postal address in every commercial email. CASL... [more]
Unsubscribe
Always include a clear and easy-to-use unsubscribe option in the body of your emails. The process should require no more than a single click, without forcing the recipient to log... [more]