Summary
Warming up a new IP address is a critical step for establishing a good sender reputation, even for transactional emails. While your gut might tell you that high-engagement transactional emails (like password resets or account activations) don't require the same rigorous warm-up process as marketing emails, this is generally incorrect. Mailbox providers assess IP reputation based on sending patterns, volume, and recipient engagement. Starting with high volumes from a cold IP can trigger spam filters and lead to delivery issues, regardless of the email content.
Key findings
- Necessity: IP warming is crucial for all email types, including transactional, to build a positive sender reputation with internet service providers (ISPs).
- Reputation building: A new IP has no prior sending history, making it susceptible to blocklisting if not properly introduced to mailbox providers. This process is essential for long-term email domain reputation.
- Engagement factor: Transactional emails typically have high engagement rates (e.g., password resets, OTPs), which can aid the warming process, but don't negate the need for it.
- Volume considerations: Even relatively low daily volumes (e.g., 1k-5k emails) can benefit from a gradual warm-up, though some experts suggest higher initial volumes are manageable with careful planning.
Key considerations
- Gradual ramp-up: Increase sending volume incrementally over time. This allows ISPs to assess your sending behavior and build trust in your new IP. For more on this, see our guide on IP warm-up strategy.
- Quality over quantity: Send to your most engaged subscribers first. This helps generate positive engagement signals, which are vital for reputation building. WP Mail SMTP provides useful IP warming email example schedules.
- Monitoring: Continuously monitor your deliverability metrics, including open rates, click-through rates, bounces, and complaints. Adjust your sending volume based on these insights.
- Authentication: Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly configured from day one. This validates your sending identity and builds trust. Learn more in our guide to DMARC, SPF, and DKIM.
What email marketers say
Marketers often face the practical challenge of warming up a new IP address for transactional emails, a task that can seem counterintuitive given the high engagement expected from these messages. While some initially believe transactional emails might be exempt from warming, the consensus leans towards a cautious approach. Discussions highlight that even with highly anticipated emails, ISPs still scrutinize new IPs for suspicious sending patterns. The key lies in balancing the immediate need for transactional email delivery with the long-term goal of building a robust sender reputation.
Key opinions
- Warm-up needed: Most marketers agree that IP warming is still necessary for transactional emails, despite their high engagement rates.
- Engagement rates: Password reset and one-time password (OTP) emails are noted for their very high engagement, which can positively influence the warm-up process.
- Volume tolerance: While some marketers suggest that low daily volumes (e.g., 1k-5k) might self-warm, others have successfully launched with significantly higher volumes (e.g., 50k-500k) on day one with extensive back-end planning.
- Triggered campaigns: A practical approach involves enabling triggered campaigns one by one, or in batches, to gradually increase volume.
Key considerations
- Risk tolerance: Launching a high volume of transactional emails without a warm-up can be heart-racing and potentially lead to deliverability issues, even if successful in some cases. Consider the risks of managing large sends without sufficient IP warmup.
- Volume management: If natural daily volume is low and gradual, a formal warm-up might not be as critical, but for higher volumes, strategies like limiting volume, round-robin sending, or flowing overflow to other IPs are important.
- Monitoring performance: Close monitoring of email performance during the initial send period is essential to identify and address any problems quickly.
- Importance of quality: As highlighted by Iterable, establishing a strong email reputation involves best practices for improving email deliverability from the start.
Marketer view
Marketer from Email Geeks questions the necessity of IP warming for exclusively transactional emails, such as password resets or account activations, coming from a brand new dedicated IP and sending subdomain, due to their transactional nature. They ponder how one would even execute a warm-up process for such emails.
Marketer view
Marketer from Email Geeks emphasizes that IP warming is still required for transactional emails, acknowledging that the process can be quite tricky. They note that sometimes, if the natural daily volume is low enough, the IP might warm itself, but otherwise, strategies like limiting volume or routing overflow through other IPs are necessary.
What the experts say
Email deliverability experts consistently advocate for IP warming regardless of email type, even for highly anticipated transactional messages. They highlight that the underlying mechanisms of IP reputation building apply universally. While transactional emails benefit from inherent high engagement, they are not immune to the scrutiny of mailbox providers. Experts emphasize that neglecting to warm up a new IP can lead to immediate deliverability challenges, underscoring the need for a structured and monitored approach.
Key opinions
- Universal need: Experts firmly state that IP warming is a necessary process for any new dedicated IP, including those used exclusively for transactional emails.
- Volume thresholds: Initial safe daily volumes are often cited around 5,000 emails per mailbox provider (MBP) per IP. Some experts are comfortable with higher initial volumes, like 50,000, for true transactional mail.
- Gradual increase: The core principle involves gradually increasing email volume over time to build a consistent and trusted sending history.
- Risk of neglect: Skipping the warm-up, especially for larger volumes, significantly increases the risk of emails being deferred, blocked, or sent to spam folders, potentially leading to deliverability issues.
Key considerations
- Start cautiously: Begin with volumes that are well within acceptable limits for a new IP, typically starting lower than your eventual peak volume.
- Monitor closely: Pay close attention to bounces, spam complaints, and temporary deferrals, as these are early indicators of reputation problems. Knowing what happens when your IP gets blocklisted is crucial.
- Quality of recipients: Even for transactional emails, ensure the recipient list is clean and consists of engaged users to maximize positive signals.
- Long-term strategy: Consider the overall sending strategy, including the potential for overflow to other IPs or shared IPs if volumes fluctuate unexpectedly. Twilio SendGrid offers a comprehensive email guide to IP warm up.
Expert view
Expert from Email Geeks indicates that sending volumes of 5,000 or fewer emails per mailbox provider (MBP) per IP per day should generally be managed without significant issues. This suggests a guideline for what can be considered a relatively safe initial volume.
Expert view
Expert from Email Geeks expresses confidence in adding up to 50,000 daily volume on a new dedicated IP for truly transactional email. However, they advise caution when the daily expected volume begins to approach 80,000 to 100,000, emphasizing these are estimates based on past experience.
What the documentation says
Official documentation from leading email service providers and deliverability experts consistently emphasizes the importance of IP warming as a foundational step for any new or unused IP address. Regardless of whether emails are transactional or marketing-oriented, the core principle remains the same: gradually increasing volume to build sender trust with mailbox providers. This process is deemed critical for establishing a positive reputation, avoiding blocklists, and ensuring high inbox placement rates. The documentation often provides best practices and strategic approaches to minimize risks during this crucial phase.
Key findings
- Reputation establishment: IP warming is fundamentally about establishing a credible IP address reputation with ISPs. This is the primary goal regardless of email content.
- Systematic volume increase: The process involves starting with low volumes and methodically increasing them over a defined period, allowing ISPs to learn and trust the new IP.
- Deliverability impact: Proper IP warm-up is directly linked to improved email deliverability, higher inbox placement, and reduced risk of emails landing in spam folders or on a blacklist.
- Best practices focus: Documentation often outlines various best practices to ensure a successful warm-up, emphasizing careful planning and execution.
Key considerations
- Authenticity: Ensure all emails are properly authenticated (SPF, DKIM, DMARC) from the very beginning of the warm-up process. This is a foundational step for trust.
- Recipient engagement: Prioritize sending to highly engaged users initially to generate positive signals and build a good reputation rapidly.
- Separate IPs: Consider maintaining separate IP addresses for transactional and marketing emails to protect the reputation of critical transactional flows. This is a best practice often cited in dedicated IP warm-up best practices.
- Data-driven decisions: Use data and analytics to monitor deliverability performance and adjust your warm-up schedule accordingly. SocketLabs highlights this in their guide on how to warm up an IP address.
Technical article
Documentation from Twilio SendGrid outlines that IP warming involves initiating email sends at low volumes from a dedicated IP, followed by a systematic and gradual increase in the email volume over a period of time. This methodical approach is designed to establish and maintain a positive sender reputation.
Technical article
Documentation from Iterable explores the significant importance of an IP warm-up process for email deliverability. It details best practices that, when followed, contribute to a stronger sender reputation and ultimately lead to improved rates of email delivery to the inbox.
Related resources
8 resources
Related pages
What are the best practices for dedicated IP warm-up?
How do I resolve temporary deferral errors and warm up new IP addresses for transactional emails on Yahoo?
How long does it take to warm up an IP address for sending 25 million emails per day?
What happens when your ip gets blocklisted?
A simple guide to DMARC, SPF, and DKIM
Why Your Emails Fail: Expert Guide to Improve Email Deliverability [2025]
What is the best IP warmup strategy for email sending?
How to warm up a dedicated IP without interrupting existing email campaigns?
Email Deliverability Issues: Getting Your Messages to the Inbox in 2025
How to consolidate email sending platforms and warm up a new IP for improved deliverability?
