Should I use hyphenated domains for email sending and how does it affect my DMARC policy?
Michael Ko
Co-founder & CEO, Suped
Published 14 Jun 2025
Updated 18 Aug 2025
8 min read
When setting up email infrastructure, one of the crucial decisions you face is choosing your domain name for sending. You might wonder if using a hyphenated domain, such as email-yourdomain.com, is a viable option, especially when compared to a standard subdomain like email.yourdomain.com. The choice has significant implications for your email deliverability and how your DMARC policy functions.
The distinction between these two formats is often misunderstood, leading to potential issues with email authentication and sender reputation. It's essential to grasp how domain structures interact with email security protocols, particularly DMARC, to ensure your messages reach the inbox reliably.
A common misconception is that a hyphenated domain acts similarly to a subdomain. However, email-yourdomain.com is a completely separate top-level domain from yourdomain.com. It requires its own registration and DNS records, just like any other unique domain. In contrast, email.yourdomain.com is a subdomain that falls under the umbrella of yourdomain.com.
The presence of a hyphen within the main domain name fundamentally changes how it's treated by DNS and, consequently, by email servers. It's not merely a different separator, but rather defines an entirely separate entity on the internet. This distinct nature means that any email authentication policies, including DMARC, do not automatically extend or inherit from your primary domain.
While email addresses can contain hyphens within the local-part (before the @ symbol) or the domain, the use of hyphens to create a seemingly related but distinct domain (a cousin domain or lookalike domain) carries significant risks. According to Debounce, dashes are allowed, but the context matters for email deliverability.
Impact on DMARC policy
Because a hyphenated domain is treated as a distinct entity, it does not inherit the DMARC policy from your main domain. This is a critical point that can lead to significant email deliverability issues if not properly addressed. Each unique domain, including hyphenated ones, requires its own SPF, DKIM, and DMARC records to ensure proper email authentication. You can learn more about how to set up DMARC records for email authentication in our comprehensive guide.
For a subdomain, you have flexibility. A subdomain can either inherit the DMARC policy of its organizational domain (the parent domain) if a sp tag is used in the parent DMARC record, or it can have its own explicit DMARC record. This is why it's important to understand when to add DMARC records for subdomains.
To illustrate, here's how a DMARC record might look for a primary domain and how a separate hyphenated domain would need its own.
This highlights why hyphenated domains pose an extra management burden and can complicate your overall DMARC strategy. A simple guide to DMARC, SPF, and DKIM can help clarify the authentication mechanisms at play.
Deliverability and reputation risks
Using hyphenated domains for email sending can severely impact your email deliverability and sender reputation. Mailbox providers and spam filters are highly sophisticated and are designed to identify suspicious sending patterns. Lookalike domains, especially those that include hyphens to mimic a primary brand, are a common tactic used by phishers and spammers. This association can lead to your emails being flagged as suspicious, routed to the spam folder, or even blocked entirely. This is one of the reasons emails fail.
Building a strong sender reputation is crucial for deliverability. When you use a hyphenated domain, you're essentially starting from scratch with a domain that already carries a higher risk perception. This makes the warming process much more challenging and prolonged. Even if your intentions are legitimate, the domain structure itself can trigger automated defenses. Being added to an email blacklist (or blocklist) is a very real risk, which can severely hinder your ability to reach recipients' inboxes. Our guide explains what happens when your domain is on an email blacklist.
The perception of hyphenated domains as potential spam or phishing attempts also extends to recipients. Users are increasingly wary of unusual domain names, especially if they resemble a known brand but have slight variations. This can lead to lower open rates, higher complaint rates, and a general distrust in your communications, regardless of your authentication setup.
Best practices and migration
The overwhelming consensus in email deliverability is to avoid hyphenated domains for sending. Instead, prioritize using standard subdomains (e.g., mail.yourdomain.com or news.yourdomain.com). Subdomains clearly indicate their relationship to your main brand, fostering trust with both recipients and mailbox providers. You can find best practices for choosing a sending domain in our detailed article.
If you are currently using a hyphenated domain for email sending, it is highly advisable to migrate to a standard subdomain structure. This migration should be approached strategically. It will involve setting up new SPF, DKIM, and DMARC records for the subdomain, and then carefully warming up the new sending domain to build its reputation. The good news is that using subdomains can improve deliverability.
The process of warming up a new domain, even a subdomain, is critical to ensure mailbox providers trust your sending volume. You can find more information on domain warming to improve domain reputation and ensure your email authentication impacts are positive.
Views from the trenches
Best practices: Always use standard subdomains (e.g., mail.yourdomain.com) for email sending to maintain clear brand association and avoid suspicion.
Common pitfalls: Mistaking hyphenated domains for subdomains and assuming DMARC policy inheritance, which can lead to authentication failures.
Expert tip: If migrating from a hyphenated domain, plan for a thorough IP and domain warming process for the new subdomain to establish a good reputation.
Expert from Email Geeks says: A hyphenated domain (e.g., email-conglomo.com) is a completely different domain, not a subdomain, and it does not inherit DMARC from your primary domain.
Expert from Email Geeks says: These 'cousin domains' or 'lookalike domains' are a bad idea because they train recipients to perceive similar, potentially fraudulent, emails as legitimate. This increases the risk of successful phishing attacks against your audience.
Marketer from Email Geeks says: Using related domains is often seen as a sign of being a spammer, as it suggests an attempt to avoid getting the primary domain into trouble or to deceive recipients.
Expert from Email Geeks says: If a recipient's anti-spam or anti-abuse team has to guess whether your domain is related to your main brand, you're already creating a problem for your deliverability.
Marketer from Email Geeks says: If a client is currently using a hyphenated domain, advising them to transition to standard subdomain formatting is crucial, even if it requires a thorough warm-up period.
Key takeaways
In summary, while technically possible to use hyphenated domains for email sending, it is strongly advised against due to significant risks to your email deliverability and sender reputation. These domains are treated as entirely separate entities, meaning they do not inherit DMARC policies and can be easily mistaken for phishing attempts.
Opting for standard subdomains is the industry best practice, offering clearer brand association, better DMARC inheritance options, and a smoother path to building and maintaining a positive sender reputation. If you are currently using a hyphenated domain, planning a careful migration to a subdomain is a worthwhile investment in your email program's long-term success.
