Summary
The answers to the question of whether to use subdomains or a single domain with multiple IPs for email sending highlight that the best approach depends on individual circumstances, with no inherently superior method. A key theme is optimizing sender reputation and deliverability, especially for growing businesses with small sending volumes. Strategies include: implementing gradual IP warm-up, improving engagement through segmentation and relevant content, consistently cleaning email lists, and adopting robust authentication methods like SPF, DKIM, and DMARC. Simplifying signup processes with no-captcha and confirmation emails is recommended. Recognizing the prevalence of freemail addresses, particularly among small businesses, is important. It's also essential to establish feedback loops to manage bounces and complaints effectively and avoid drastic changes to the 'From:' domain due to brand recognition impact.
Key findings
- Contextual Choice: The choice between subdomains and a single domain with multiple IPs depends on specific organizational needs.
- Authentication is Key: Proper implementation of SPF, DKIM, and DMARC is critical for building trust with mailbox providers.
- IP Warm-up Matters: A gradual IP warm-up is essential for new IPs or domains to build a positive sender reputation.
- Engagement Drives Deliverability: Improving email engagement (opens, clicks) is critical for better deliverability.
- List Cleaning: Regularly cleaning email lists to remove inactive or invalid addresses is a must.
- Simplified Signup: Simplifying signup with no-captcha and confirmation emails is recommended.
Key considerations
- Domain Strategy: Carefully consider the implications of using subdomains vs. a single domain; subdomains can segment reputation, but require proper management.
- Authentication Setup: Ensure SPF, DKIM, and DMARC are correctly configured and maintained for all sending domains and subdomains.
- Sender Reputation: Proactively monitor sender reputation by tracking bounce rates, complaint rates, and engagement metrics.
- Signup Process: Optimize signup processes to minimize friction and maximize legitimate sign-ups.
- Segmentation and Personalization: Segment your audience and personalize content to increase relevance and engagement.
- Adaptation: Be aware of practices of your userbase, adapting to their email usage, such as freemail.
What email marketers say
12 marketer opinions
The central question explores the strategic choice between using subdomains versus a single domain with multiple IPs for email sending, alongside optimizing signup processes and sender reputation for growing businesses with small sending volumes. The responses highlight that there isn't a definitively superior method; the best approach depends on the organization's specific needs and challenges. Key strategies for optimization include gradual IP warm-up, improving email engagement, regular list cleaning, implementing DMARC, A/B testing signup forms, and using double opt-in. Managing sender reputation through authentication and monitoring bounce/complaint rates is also crucial, as is catering to different email user bases, even if they use freemail providers.
Key opinions
- Subdomain Segmentation: Using subdomains can help segment email traffic, protecting the main domain's reputation by isolating the impact of individual campaigns.
- Gradual IP Warm-up: A gradual IP warm-up is critical for new domains/IPs to establish a positive sending reputation with ISPs.
- Email Engagement: Improving email engagement through relevant content, list segmentation, and encouraging recipients to add the sender to their address book is crucial for deliverability.
- List Hygiene: Regularly cleaning email lists by removing inactive or invalid addresses improves sender reputation and deliverability.
- DMARC Implementation: Implementing DMARC is essential for protecting domain reputation by specifying how email receivers should handle unauthenticated messages.
- Optimized Signup Forms: A/B testing signup forms and ensuring a simple, user-friendly process helps increase conversion rates.
- Double Opt-In: Using a double opt-in process ensures subscribers genuinely want to receive emails, improving engagement and reducing spam complaints.
Key considerations
- Organizational Needs: The choice between subdomains and a single domain with multiple IPs depends on the organization's specific requirements and deliverability challenges.
- Authentication Setup: Proper email authentication (SPF, DKIM, DMARC) is essential for building trust with mailbox providers and improving deliverability.
- Monitoring Sender Reputation: Regularly monitor bounce rates, complaint rates, and engagement metrics to proactively address deliverability issues.
- Catering to User Base: Acknowledge that some users, particularly in SMBs, may use freemail addresses and adapt strategies accordingly.
- Segmentation and Personalization: Segment your audience and personalize email content to increase engagement and relevance.
- New IP/Domain Considerations: If using new IPs or domains, implement a gradual IP warm-up strategy to avoid deliverability problems.
Marketer view
Email marketer from Mailjet Blog shares that for new domains or IPs, a gradual IP warm-up is critical. Starting with low volumes and slowly increasing the number of emails sent each day helps establish a positive sending reputation with ISPs. Focusing on engagement (opens, clicks) and avoiding spam complaints is essential during this process.
12 Apr 2024 - Mailjet Blog
Marketer view
Email marketer from Email Geeks mentions that SMBs overwhelmingly use Gmail addresses because they don’t know how to connect the dots to make email work for their own domain.
6 Jul 2024 - Email Geeks
What the experts say
6 expert opinions
The collective expert advice focuses on practical strategies and key considerations for managing email deliverability. For signup processes, implementing no-captcha and confirmation emails is recommended over third-party verification. Maintaining existing domain reputation is favored over changing the 'From' domain, even if it's a freemail provider like Gmail, which is common among small businesses. IP warm-up, email authentication (SPF, DKIM, DMARC), and monitoring engagement metrics are essential for sender reputation. Managing mailing lists and establishing feedback loops are also key.
Key opinions
- Simplified Signup: No-captcha and confirmation emails suffice for signup, replacing third-party verification.
- Domain Reputation: Maintaining existing domain reputation is preferred over changing the 'From' domain.
- Freemail Prevalence: Small businesses commonly use Gmail addresses, requiring consideration in email strategies.
- IP Warm-up: Gradual IP warm-up is crucial for new IPs or domains to establish a positive sending reputation.
- Email Authentication: Proper email authentication (SPF, DKIM, DMARC) is paramount for trust and deliverability.
Key considerations
- Signup Process: Prioritize user-friendly signup processes to reduce friction.
- Domain Choice: Carefully consider the impact of changing the 'From' domain on existing reputation and brand recognition.
- Authentication Configuration: Ensure SPF, DKIM, and DMARC are correctly configured for all sending domains.
- Reputation Management: Monitor engagement metrics and address bounces/complaints to maintain a healthy sender reputation.
- Feedback Loops: Establish feedback loops to receive notifications about complaints and bounces promptly.
Expert view
Expert from Email Geeks states that changing the From: domain is not a great idea, as it’s discarding all their history and reputation and brand recognition, even if the From: domain is gmail.com.
28 Feb 2025 - Email Geeks
Expert view
Expert from Word to the Wise emphasizes the importance of IP warm-up, particularly when using new IPs or domains. Gradual increases in sending volume and monitoring engagement metrics are crucial. They also address the impact of bounces and complaints on sender reputation, urging proactive management of mailing lists and the establishment of feedback loops.
27 Jul 2023 - Word to the Wise
What the documentation says
4 technical articles
The documentation collectively emphasizes the importance of proper email authentication, managing sender reputation, and understanding subdomain behavior. Subdomains can inherit reputation from parent domains but also establish their own, and they require proper authentication (SPF, DKIM). Maintaining low bounce and complaint rates through feedback loops and prompt removal of hard bounces is also crucial.
Key findings
- Subdomain Reputation: Subdomains inherit reputation but can also establish their own, affecting parent domains if misused.
- SPF for Subdomains: Subdomains can have their own SPF records for delegated sending authority.
- DKIM Configuration: DKIM should be properly configured for both main domains and subdomains.
- Bounce/Complaint Rates: Low bounce and complaint rates are crucial for sender reputation.
- Feedback Loops: Setting up feedback loops enables monitoring of complaints and bounces.
Key considerations
- Authentication: Ensure proper SPF, DKIM, and DMARC configuration for all sending domains and subdomains.
- Subdomain Management: Manage subdomain sending practices to prevent negative impact on parent domain reputation.
- Reputation Monitoring: Continuously monitor sender reputation metrics to identify and address issues promptly.
- Key Rotation: Rotate DKIM keys periodically to enhance security.
- Bounce Handling: Promptly remove addresses that generate hard bounces from your mailing lists.
Technical article
Documentation from AWS details that maintaining low bounce and complaint rates is crucial for sender reputation. Set up feedback loops to receive notifications about complaints and bounces. Immediately remove addresses that generate hard bounces from your list to prevent further deliverability issues.
25 May 2025 - Amazon Web Services Documentation
Technical article
Documentation from RFC 4408 defines the Sender Policy Framework (SPF) and how it applies to subdomains. It explains that subdomains can have their own SPF records, allowing for delegation of sending authority. This is important for managing sender authentication across different parts of your organization or for different email streams.
14 Mar 2023 - RFC 4408
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