Summary
To optimize email deliverability, new senders or those using new IPs or domains should always begin with low email volumes and gradually increase their sending over time. While specific initial volumes vary, ranging from single digits or 10-20 emails for domains to several hundreds or even thousands for new dedicated IPs, the underlying principle is to start small and incrementally expand. Daily increases typically range from 10-50%, or doubling every few days, over a period of several weeks, usually between two and eight weeks. Throughout this warm-up phase, it's critical to send only to highly engaged subscribers and diligently monitor deliverability metrics such as bounces and complaints to guide the pace. Factors like whether it's a new domain or IP, and the specific mailbox provider's unwritten rules, also influence the ideal strategy.
Key findings
- Varying Initial Volumes: Recommended initial email sending volumes vary widely, from as low as single digits or 10-20 emails for new domains, to 50-200 emails per day for general warm-up, and up to 500-1,000 or even 5,000-10,000 emails per day for new dedicated IPs according to some ESPs.
- Gradual Volume Increase: There is a strong consensus on the need to gradually increase sending volume. Recommendations for daily increases range from 10-20%, 25-50%, or doubling every few days, depending on the sender's reputation and monitoring results.
- Extended Warm-up Period: The warm-up process is not immediate; it typically spans several weeks to months, with common recommendations ranging from 2-4 weeks, 4-6 weeks, or even 4-8 weeks to reach full desired sending volume.
- Importance of Reputation Building: Initial low-volume sending combined with high engagement is crucial for establishing a positive sender reputation and trust with Internet Service Providers (ISPs) and mailbox providers, preventing emails from being flagged as spam.
Key considerations
- Domain and IP Type: The ideal initial sending volume is significantly influenced by whether you are using a brand new domain, a subdomain, or an existing sending domain, as well as if you are warming up a new dedicated IP address versus using a shared IP.
- Subscriber Engagement: Prioritize sending to your most engaged subscribers during the initial warm-up phase to demonstrate positive sending behavior and build a strong sender reputation with mailbox providers.
- Monitoring Metrics: Continuously monitor key deliverability metrics such as bounce rates, spam complaints, and engagement levels. Adjust your sending volume and pace based on these performance indicators, pausing or slowing down if issues arise.
- Mailbox Provider Specifics: Be aware that some mailbox providers, like Gmail, may have specific unwritten recommendations, such as starting with very low volumes, even single digits, on the first day.
- Consistency over Speed: While clients often want to send quickly, consistent and gradual increases in sending volume are more critical for long-term deliverability than aggressive scaling. Avoid sudden spikes in volume, which can trigger spam filters.
What email marketers say
11 marketer opinions
To effectively build sender reputation and ensure email deliverability, the consensus among experts is to initiate sending with very low volumes and progressively escalate. While specific starting points vary, often beginning from as few as 10-20 emails or up to a few hundred on the first day, the core strategy involves slow, consistent increases. Daily volume increments typically fall between 10-30%, though some suggest doubling every few days, over a warm-up period that commonly spans 4 to 8 weeks. This careful approach, coupled with sending to highly engaged segments, helps establish trust with mailbox providers and avoid triggers for spam filters, which can result from sudden high-volume sends.
Key opinions
- Varied Starting Points: Initial recommended sending volumes for new email setups vary, with some experts suggesting starting as low as 10-20 emails for new domains, while others advise beginning with 50-200 emails, or even a few hundred up to 500-1000 for new IPs, on the first day.
- Gradual Volume Increase Pace: Email volume should be increased incrementally, with common recommendations ranging from a 10-30% daily increase. Some experts suggest doubling volume every few days, while also emphasizing rate limiting, such as 5-10 emails per hour for very low initial sends.
- Extended Warm-up Duration: The warm-up process typically extends over several weeks, with most recommendations falling within a 4-8 week timeframe to gradually reach full desired sending volume and establish a solid reputation.
- Prioritize Engaged Subscribers: Consistently sending to the most engaged segments of your audience during warm-up is crucial for demonstrating positive sending behavior and building a strong sender reputation with Internet Service Providers (ISPs).
Key considerations
- Domain and IP Type: The ideal initial volume and warm-up strategy can depend on whether you are using a brand new domain, a subdomain, or a previously used sending domain, as well as if you're warming a new dedicated IP.
- Avoid Sudden Volume Spikes: Rapidly increasing email volume or sending large bursts can trigger spam filters and negatively impact sender reputation; consistency and gradualism are preferred.
- Continuous Performance Monitoring: Closely monitor deliverability metrics, including bounce rates, spam complaints, and engagement, throughout the warm-up period, adjusting sending pace and volume as needed to mitigate any issues.
- Building Mailbox Provider Trust: The primary goal of gradual warm-up is to build trust and a positive reputation with mailbox providers, demonstrating consistent, legitimate sending practices over time.
Marketer view
Email marketer from Email Geeks recommends that starting with 10-20 emails is ideal, while acknowledging that clients often prefer to send as quickly as possible.
16 Jul 2022 - Email Geeks
Marketer view
Email marketer from Email Geeks explains that the ideal initial sending volume also depends on factors such as whether it's a brand new domain, a subdomain, or the same sending domain used previously with a different vendor.
9 Apr 2022 - Email Geeks
What the experts say
4 expert opinions
Establishing robust email deliverability from the outset necessitates a cautious approach to initial sending volumes, emphasizing a slow and deliberate increase. Industry experts and mailbox providers consistently advise beginning with minimal message counts, whether for a new domain or IP, to cultivate a positive sender reputation. This foundational period involves starting with very small batches, typically a few hundred or even single digits, and gradually expanding volume, often by 25-50% daily or doubling every few days, while prioritizing engaged recipients and closely monitoring performance.
Key opinions
- Low Initial Volumes: Initial sending recommendations range from "single digits" for services like Gmail to a "few hundred or a thousand messages" per day, particularly for new IPs, with the goal of establishing trust.
- Consistent, Gradual Increases: Experts universally advise a slow ramp-up, suggesting daily increases of 25-50% or doubling volumes every few days or weekly, rather than aggressive scaling.
- Engagement as a Priority: Sending only to highly engaged subscribers during the initial warm-up phase is crucial for demonstrating positive sending behavior and building a strong sender reputation.
- Unwritten Rules and Practices: Deliverability practices, especially with major mailbox providers like Gmail, often involve unwritten recommendations that differ from official documentation, underscoring the need for careful observation.
Key considerations
- Monitoring Sender Reputation: Continuous monitoring of sender reputation and engagement rates is vital, allowing for adjustments in sending volume based on performance indicators.
- Prioritizing Consistency: Maintaining consistent sending patterns and avoiding sudden, large volume increases is more critical for long-term deliverability than rapid scaling.
- Adapting to Mailbox Provider Specifics: Be aware that different mailbox providers may have unique, informal guidelines, such as Gmail's suggestion for extremely low initial volumes, influencing the warm-up strategy.
- Strategic Warm-up Goals: The primary objective of initial low-volume sending is to build trust and demonstrate legitimate sending behavior to mailbox providers, ensuring future emails reach the inbox.
Expert view
Expert from Email Geeks explains that some ESPs, including Salesforce, advocate for starting with low email volumes. She notes that for 4-5 years, Gmail representatives have recommended sending “single digits to Gmail on day one” and that deliverability team practices often differ from published documentation.
16 Aug 2022 - Email Geeks
Expert view
Email expert from Quora (Chad S. White) explains that there's no fixed rule, but for a new IP, one should start with volumes low enough to get high engagement rates (e.g., a few thousand) and gradually increase by 25-50% per day, monitoring reputation closely. Consistency and engagement are more critical than aggressive scaling.
8 Jul 2022 - Quora
What the documentation says
6 technical articles
Major Email Service Providers (ESPs) and deliverability experts universally advocate for a meticulous warm-up process when establishing new email sending infrastructure, whether a fresh IP or domain. The core recommendation involves initiating sending with conservative volumes to a highly engaged audience, then progressively escalating the message count over a period of weeks or months. While initial daily volumes suggested by providers vary, typically ranging from a few hundred to several thousand emails, the common thread is a gradual daily increase, often between 10-20% or even doubling every few days. This disciplined approach, coupled with vigilant monitoring of key deliverability metrics, is paramount for cultivating a robust sender reputation and ensuring emails consistently reach the inbox.
Key findings
- Varying Initial Volume Guidance: While all sources recommend starting small, initial daily volumes vary; some suggest a few hundred emails (Postmark, Iterable), while others recommend several thousand (Mailchimp, SendGrid) for new dedicated IPs.
- Consistent Gradual Increases: There's a consensus on increasing volume incrementally, typically by 10-20% daily or every few days. Some suggest doubling volumes, adjusting based on observed reputation and engagement.
- Extended Warm-up Duration: The warm-up period is consistently cited as lasting several weeks, commonly 2-4 weeks to reach significant volumes, with some acknowledging it could extend to several months for full reputation maturity.
- Reputation Building is Core: Every email service provider emphasizes that the primary goal of the warm-up process is to establish and cultivate a positive sender reputation and build trust with major mailbox providers.
Key considerations
- Prioritize Engaged Subscribers: During the initial warm-up phase, always send to your most engaged subscribers to demonstrate positive sending habits and build a strong reputation with Internet Service Providers (ISPs).
- Monitor Performance Continuously: Vigilantly track key deliverability metrics like bounce rates, spam complaints, and engagement. Use these insights to adjust your sending pace and volume as needed, slowing down if issues arise.
- Avoid Sudden Volume Spikes: Rapidly increasing email volume can harm your sender reputation and trigger spam filters. A gradual, consistent ramp-up is critical for long-term success.
- Adaptability is Key: The warm-up schedule is not rigid; it should be flexible and responsive to real-time deliverability performance and reputation feedback from mailbox providers.
Technical article
Documentation from Mailchimp explains that IP warm-up is crucial for new sending IPs. They recommend starting with small batches of highly engaged subscribers and gradually increasing volume over several weeks or months. For a new IP, they suggest starting with a few thousand emails per day and doubling every few days, depending on reputation.
11 Feb 2022 - Mailchimp
Technical article
Documentation from SendGrid explains that warm-up is essential for new IPs or domains to build reputation. They provide a sample warm-up schedule, suggesting starting with 5,000-10,000 emails per day for the first few days, then gradually increasing by 10-20% daily, aiming to reach full volume within 2-4 weeks.
1 Mar 2022 - SendGrid
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