Summary
When launching a new email program with a zero-based subscriber list on a shared IP address, the traditional process of IP warming is generally not required. IP warming is primarily a strategy for establishing sender reputation for a new, dedicated IP address, or when migrating a large, existing subscriber list to a new sending infrastructure. Since a shared IP already has an established reputation from other senders, and a zero-based list means you'll be gradually growing your volume from scratch, the inherent nature of your sending activity will act as a natural, organic warm-up process.
Key findings
- Shared IP benefits: Shared IPs come with a pre-established sender reputation, as they are used by multiple senders. This negates the need for a dedicated IP warming schedule.
- Zero-based list: Starting with no existing subscribers means your sending volume will naturally increase over time as your list grows, effectively warming the domain and your sending practices without a formal IP warm-up plan.
- Focus on list growth: Your primary focus should be on organic list acquisition and maintaining high engagement rates, which are crucial for long-term deliverability.
- Domain reputation matters: While IP warming isn't critical here, establishing a strong domain reputation from day one is essential. This includes consistent email authentication (SPF, DKIM, DMARC) and sending relevant content.
Key considerations
- List quality: Always prioritize collecting high-quality, opted-in subscribers, as this directly impacts engagement and sender reputation. Even on a shared IP, poor sending practices can lead to issues, including placement on a blocklist or blacklist.
- Engagement monitoring: Closely monitor engagement metrics like open rates, click-through rates, and complaint rates. Healthy engagement helps build positive sender reputation.
- Authentication protocols: Ensure your domain is properly configured with SPF, DKIM, and DMARC. These are fundamental for email deliverability regardless of IP type. Mailgun's blog highlights that robust authentication helps establish sender credibility and is a key component of domain reputation (Mailgun, Domain warm-up and reputation: Stretch before you send).
- Volume consistency: Even without formal warming, avoid sudden, large spikes in sending volume. Allow your list to grow naturally and scale your sending proportionally.
What email marketers say
Email marketers widely agree that IP warming is not a necessary step when launching a new email program with a zero-based list on a shared IP address. Their consensus points to the fact that the very definition of IP warming involves gradually increasing sending volume on a new, dedicated IP to build its reputation with internet service providers (ISPs). When starting from scratch on a shared IP, this controlled ramp-up naturally aligns with the organic growth of a new subscriber base, making a separate warming process redundant.
Key opinions
- No existing volume: Many marketers highlight that IP warming is about restricting volume to build trust. If you're starting from zero, there's no volume to restrict, so the traditional warming process doesn't apply.
- Shared IP functionality: The shared IP already has a sending history and reputation, managed by the email service provider (ESP). This allows new senders to leverage that existing trust, bypassing the need for individual IP warming.
- Focus on content and engagement: Instead of IP warming, marketers advise focusing on building a high-quality, engaged subscriber list through good acquisition practices and valuable content.
- Migration vs. New launch: There's a clear distinction drawn between migrating an established list (which necessitates IP warming) and launching a brand new program (where it's not needed).
Key considerations
- Understand warming purpose: Clients often confuse IP warming with general email deliverability best practices. It's important to explain that warming applies specifically to new dedicated IPs or large list migrations, as discussed in the context of Iterable's guide to IP warming.
- List acquisition strategies: Marketers should focus on ethical and effective ways to build their subscriber list from zero. This includes clear opt-in processes and managing expectations for initial list size.
- Reputation building: Even without IP warming, attention to other factors like domain and IP reputations is paramount to ensure messages land in the inbox.
- Long-term strategy: Plan for sustainable list growth and consistent sending frequency to maintain good sender health over time. Sudden increases in volume, even on a shared IP, can sometimes trigger spam filters if not managed well.
Marketer view
Email marketer from Email Geeks explains that if a new brand's email program starts with a list that genuinely begins at zero and grows naturally from there, then traditional IP warming isn't necessary. The core purpose of warming is to gradually increase volume, but with no initial volume to restrict, the process becomes redundant. The natural growth of the list serves a similar function.
Marketer view
Email marketer from Email Geeks confirms that if a new program truly starts from zero subscribers, there's no need for an IP warm-up. The concept of warming applies when you have existing email addresses that you need to introduce to a new sending infrastructure. Without a pre-existing list, there's simply nothing to warm up in that traditional sense.
What the experts say
Email deliverability experts concur that IP warming is specifically designed to build reputation for a new or cold dedicated IP address. When starting a new email program with a zero-based list on a shared IP, the logic of IP warming doesn't apply. Shared IPs are managed by the ESP, which handles the collective reputation of multiple senders on that IP. Therefore, the focus shifts from IP warming to maintaining excellent sending practices, ensuring list quality, and building strong domain reputation from the outset.
Key opinions
- Dedicated IP context: Experts consistently emphasize that IP warming is a process tied to introducing a *new, dedicated IP address* to ISPs to build its sending history and reputation.
- Shared IP's existing reputation: A shared IP or IP pool already carries an established reputation from its ongoing use by other senders, meaning a separate warming phase for a new sender on that IP is redundant.
- Organic growth: For a zero-based list, the natural, gradual increase in sending volume as the list grows organically serves as its own form of reputation building, albeit not a formal IP warm-up in the traditional sense.
- Volume control on dedicated IP: If, hypothetically, a zero-based list were to be sent from a brand new *dedicated* IP, experts advise a slow, progressive increase in volume, throttling sends daily if needed, to build a positive reputation with ISPs.
Key considerations
- Reputation management: Even on shared IPs, sender behavior heavily influences deliverability. Experts advise vigilance over metrics such as bounce rates, spam complaints, and unsubscribe rates to maintain good standing.
- Avoiding blocklists: While IP warming isn't for shared IPs, poor sending practices can still lead to your domain or even the shared IP being placed on a blocklist or blacklist. Understanding how email blocklists work is essential.
- Authentication standards: Ensure all email authentication protocols like SPF, DKIM, and DMARC are correctly set up. ISPs rely heavily on these signals to verify sender legitimacy, as noted by SpamResource in their IP Warming Guide, even if it is for dedicated IP warming, the underlying principles apply.
- Data quality: A clean, engaged list is the foundation of good deliverability. Continuously monitoring list health and removing unengaged subscribers is a best practice for any sending environment.
Expert view
Email expert from Email Geeks clarifies that IP warming is designed to introduce a new IP address to the receiving mail servers. They emphasize that if you are using a shared IP or an IP pool, this warming process is unnecessary because the IP already has a history and reputation established by the ESP.
Expert view
Email expert from Email Geeks provides a critical nuance: if you are growing your list from zero but on a *brand new dedicated IP*, then you absolutely must ensure your sending volume grows slowly and progressively. They recommend throttling by day if necessary to gradually build the IP's reputation with various internet service providers (ISPs).
What the documentation says
Official documentation from leading email service providers and deliverability resources consistently clarifies that IP warming is a process specifically for dedicated IP addresses, or for migrating large existing volumes to a new infrastructure. For email programs starting fresh with a zero-based list on a shared IP, the ESP manages the IP's reputation. The guidance universally points to focusing on quality list acquisition, consistent sending, and strong email authentication as the primary drivers of deliverability, rather than a formal IP warm-up strategy.
Key findings
- Shared IP exemption: Documentation from major ESPs explicitly states that IP warming is not required for shared IP addresses, as their reputation is collectively managed.
- Dedicated IP prerequisite: The need for IP warming arises when a sender acquires a new, dedicated IP address that has no prior sending history, necessitating a gradual introduction to ISPs.
- Organic ramp-up: For new programs with zero lists, the process of acquiring subscribers and incrementally increasing sending volume acts as a natural, informal warming, building domain reputation over time.
- Focus on content and hygiene: Documentation emphasizes the importance of sending high-quality, engaging content to a clean, opted-in list as the cornerstone of good deliverability, regardless of the IP type.
Key considerations
- Sender reputation factors: While IP warming may not be needed, ISPs still evaluate sender reputation based on engagement, spam complaints, and bounce rates. These factors are critical for any sending program, as highlighted by Twilio SendGrid's email guide.
- Authentication configuration: Proper configuration of email authentication protocols (SPF, DKIM, DMARC) is non-negotiable for deliverability. These standards help prove sender legitimacy and are vital for inbox placement.
- Domain vs. IP reputation: Documentation often distinguishes between IP and domain reputation. On shared IPs, your domain's reputation becomes the primary focus for mailbox providers, underscoring the importance of good sending practices associated with your specific domain.
- Scalability and thresholds: While no formal warming, new programs should still monitor their sending volumes and engagement. If a brand eventually scales to very high volumes, they might consider a dedicated IP, which would then necessitate a formal warm-up, as described by Ongage's blog on IP warming.
Technical article
Documentation from Twilio SendGrid clarifies that senders typically use shared IPs for lower email volumes, and these do not require individual IP warming. The need for a dedicated IP and its associated warming process only arises when an organization reaches higher sending volumes that warrant individual IP reputation management.
Technical article
Documentation from Mailgun states that their shared IP addresses do not require a warm-up period because they are already operational and carry an established reputation. This allows new users to begin sending without the typical gradual volume ramp-up associated with new, dedicated IPs.
Related resources
4 resources
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