Summary
Using multiple synonym domains for email campaigns is generally considered risky for deliverability. Experts, marketers, and technical documentation all point to a potential dilution of sender reputation, increased complexity in managing authentication (SPF, DKIM, DMARC), and a higher likelihood of triggering spam filters. Multiple domains can confuse recipients, making them vulnerable to phishing, while consolidating efforts under a single, well-managed domain or using subdomains is generally recommended for better brand consistency, streamlined authentication, and improved deliverability.
Key findings
- Diluted Sender Reputation: Multiple domains dilute sender reputation, making it harder to build trust with mailbox providers.
- Increased Complexity: Managing authentication protocols (SPF, DKIM, DMARC) across multiple domains is complex and increases the potential for errors.
- Spam Filter Risk: Multiple domains can trigger spam filters, especially if they appear similar or are used for unwanted content.
- Subdomains Recommended: Subdomains are preferred because they inherit the reputation of the main domain and offer better brand consistency.
Key considerations
- Brand Consistency: Consider whether different domains will confuse recipients or make your brand vulnerable to phishing attempts.
- Authentication Management: Assess whether you have the resources and technical expertise to manage authentication protocols effectively across multiple domains.
- Content Strategy: Avoid sending unexpected or unwanted content from synonym domains, as this can raise red flags with spam filters.
- Long-Term Strategy: Evaluate if the benefits of using multiple domains outweigh the potential risks to deliverability and brand reputation. A single, well-managed domain often provides better long-term results.
What email marketers say
13 marketer opinions
Using multiple synonym domains for email sending presents several risks to deliverability. It can dilute sender reputation, trigger spam filters, and confuse recipients. Managing authentication (SPF, DKIM, DMARC) across multiple domains is complex, and building trust is harder with inconsistent branding. Consolidating email efforts under a single, well-managed domain or using subdomains is generally recommended for better deliverability and brand consistency.
Key opinions
- Reputation Dilution: Multiple domains dilute sender reputation, making it harder to establish trust with mailbox providers.
- Spam Filter Triggers: Using many similar domains is a tactic used by phishers and can trigger spam filters.
- Authentication Complexity: Managing SPF, DKIM, and DMARC across multiple domains is complex and prone to errors.
- Subdomains Preferred: Subdomains are generally preferred over cousin domains as they inherit the reputation of the main domain.
Key considerations
- Brand Consistency: Consider if different domains will confuse recipients and damage brand perception. Consistent branding is crucial for building trust.
- Sender Reputation Management: Assess whether you have the resources to build and maintain a positive sender reputation for each domain.
- Alternative to Multiple Domains: Explore subdomains as a structured alternative to manage different email streams while preserving your brand's reputation.
- Content type: Consider if any of your content would be unexpected as this can cause the filters to assume all domains are connected.
Marketer view
Email marketer from Email Geeks shares that if you send any type of content which would be unexpected and/or unwanted then you run the risk of the ML based filters working out that all of the domains are logically connected.
21 Mar 2022 - Email Geeks
Marketer view
Email marketer from StackOverflow explains that using multiple domains for the same brand can dilute your sender reputation and make it harder for email providers to identify you as a legitimate sender. Stick to a primary domain with well-configured authentication (SPF, DKIM, DMARC) for better deliverability.
30 Jan 2022 - StackOverflow
What the experts say
2 expert opinions
Experts agree that using multiple 'cousin' or synonym domains is risky for email deliverability. These domains can be seen negatively by mailbox providers, especially without a strong history or clear purpose. It's recommended to focus on building reputation with a smaller set of well-managed domains or using subdomains, which inherit the reputation of the main domain and prevent brand reputation dilution.
Key opinions
- Negative Signal: Multiple cousin domains can be seen as a negative signal by mailbox providers.
- Reputation Dilution: Separate sending domains can dilute the brand reputation.
- Subdomains Preferred: Using subdomains is best as they inherit the reputation of the main domain.
Key considerations
- Domain History: Consider the history and purpose of each domain. Weak or unclear purpose can hurt deliverability.
- Domain Management: Assess your ability to properly manage and build reputation for each domain. Prioritize quality over quantity.
- Alternative Approach: Consider subdomains as a structured alternative to separate sending needs while maintaining a consistent brand reputation.
Expert view
Expert from Word to the Wise explains that using multiple 'cousin' domains can be seen as a negative signal by mailbox providers, especially if those domains don't have a strong history or clear purpose. It's generally better to focus on building reputation on a smaller set of well-managed domains or subdomains.
25 Aug 2023 - Word to the Wise
Expert view
Expert from SpamResource shares that using subdomains is always best as it inherits the reputation of the main domain. Also, using separate sending domains should be avoided unless required as it dilutes the brand reputation.
9 May 2024 - SpamResource
What the documentation says
4 technical articles
Technical documentation emphasizes the risks of using multiple domains for email deliverability. Google, Microsoft, and DMARC.org all highlight the fragmentation of sender reputation and increased complexity in managing authentication protocols like SPF and DMARC. Maintaining separate SPF records and DMARC policies for each domain adds overhead and potential errors, and can trigger spam filters due to difficulty in verifying sender identity. Consistent sending from a single domain is crucial for building a positive reputation.
Key findings
- Fragmented Reputation: Multiple domains fragment sender reputation, hindering the ability to establish a positive reputation with mailbox providers like Gmail.
- Authentication Overhead: Managing SPF and DMARC across multiple domains increases complexity and potential for errors.
- Verification Difficulties: Using too many domains makes it harder for providers like Microsoft to verify sender identity, increasing the likelihood of triggering spam filters.
- Domain-Specific Policies: DMARC policies are applied per-domain, requiring careful planning for consistent enforcement across multiple domains.
Key considerations
- Resource Allocation: Assess the resources required to manage and monitor authentication for each domain.
- Technical Expertise: Ensure you have the technical expertise to properly configure and maintain SPF, DKIM, and DMARC records across multiple domains.
- Reputation Monitoring: Implement monitoring systems to track the reputation of each domain and identify deliverability issues early.
- Authentication Strategy: Consider how you will consistently enforce email security policies across all sending domains.
Technical article
Documentation from Google Postmaster Tools explains that having a consistent sending domain helps build a positive reputation with Gmail. Using multiple domains can fragment your reputation and potentially harm deliverability.
7 Jan 2023 - Google Postmaster Tools
Technical article
Documentation from DMARC.org explains that DMARC policies are applied on a per-domain basis. Managing DMARC across multiple domains requires careful planning and monitoring to ensure consistent enforcement of your email security policies.
27 Nov 2023 - DMARC.org
Are custom sending domains worth the money and effort?
Can a competitor damage my domain reputation by sending spam with my URL?
Do I need to re-warm up my IP when changing domain extension?
How does domain reputation affect email deliverability compared to IP reputation?
How does domain reputation affect subdomain reputation in email marketing?
Should I use a separate domain or subdomain for bulk email sending?
