What deliverability improvement can be expected from using dedicated vs shared IPs?

Key findings

• No guarantee: A dedicated IP does not inherently resolve existing deliverability problems, as most issues stem from sender behavior rather than shared IP pools.
• Sender control: Dedicated IPs provide complete control over your sender reputation, which is influenced solely by your sending practices. This contrasts with shared IPs, where the actions of other senders can impact your deliverability, for better or worse.
• Volume threshold: Dedicated IPs are generally recommended for high-volume senders, typically those sending millions of emails per month, as this volume allows for the consistent activity needed to build and maintain a strong reputation.
• Risk mitigation: A key benefit of dedicated IPs is the ability to mitigate the risk of being affected by other users' poor sending habits on a shared IP (or shared blocklist). This provides a more stable sending environment.
• Reputation visibility: Tools like Google Postmaster Tools allow senders to monitor the reputation of their IPs and domains, helping to determine if a dedicated IP is truly necessary. If shared IP reputation is already high, a switch might not yield significant improvements.
• Warm-up period: New dedicated IPs require a careful warm-up period to build a positive reputation with internet service providers (ISPs), which means gradually increasing sending volume over time. This can lead to a temporary dip in deliverability.
• Domain reputation: While IP reputation is important, domain reputation often plays a more significant role in inbox placement and is less tied to the underlying IP address.

Key considerations

• Current problems: Evaluate if you are experiencing specific IP-related blocks or poor inbox placement before considering a dedicated IP. If not, the benefits might be minimal.
• Sending volume consistency: Dedicated IPs thrive on consistent, high-volume sending. Erratic sending patterns or low volumes can negatively impact reputation more quickly on a dedicated IP than on a shared one.
• Management overhead: Managing a dedicated IP requires more active oversight of sending practices, engagement metrics, and blocklist monitoring to maintain a healthy reputation.
• Cost versus benefit: Weigh the additional cost of a dedicated IP against the potential benefits, particularly if current deliverability on shared IPs is already good. Focus on the ROI in terms of risk mitigation rather than guaranteed deliverability boosts.
• Transition period: Be prepared for a managed transition and potential temporary dips in inbox placement during the IP warm-up phase.

Key opinions

• No silver bullet: Many marketers agree that simply moving to a dedicated IP does not automatically fix underlying deliverability issues, which are often related to sender practices like list quality or content.
• Volume considerations: For senders approaching or exceeding 1 million emails per month, a dedicated IP is often seen as a logical next step to gain more control and stability.
• Risk mitigation: A significant advantage of dedicated IPs cited by marketers is the mitigation of risk from other senders on a shared pool, protecting their sending reputation from external factors.
• Control and predictability: Dedicated IPs offer greater control over sender reputation, leading to more predictable and consistent delivery rates compared to shared IPs.
• Cost justification: Marketers often look for clear ROI to justify the additional cost of a dedicated IP, focusing on the financial impact of potential blocks on shared IPs.
• Warm-up challenges: The need for a gradual warm-up period is a common concern, as it can temporarily impact inbox placement and requires careful management.

Key considerations

• Current performance: Before switching, evaluate if you're currently experiencing IP-related blocks or low inbox placement. If your shared IP performance is good, the benefit might not outweigh the cost and effort.
• Sending practices: Ensure your email program has strong sending practices, including list hygiene and engaging content, as these are more critical for deliverability than the IP type itself.
• Volume stability: Consider if your sending volume is consistent enough to support a dedicated IP. Large fluctuations or low volume can quickly degrade a dedicated IP's reputation.
• Monitoring tools: Leverage tools like Google Postmaster Tools to monitor your current IP reputation. If it's consistently high, the ROI for a dedicated IP may be limited.
• Strategic move: View a dedicated IP as a strategic investment for long-term control and risk management, especially for high-value email programs, rather than a quick fix. As this SendGrid blog suggests, it is about choosing a winning IP strategy.

Key opinions

• Sender behavior is key: Experts generally agree that the sender's practices, such as list hygiene, content quality, and engagement, have a greater impact on deliverability than the type of IP used.
• Volume dictates choice: Dedicated IPs become more justifiable and effective at higher sending volumes (e.g., millions per month), where consistent sending can build a strong, isolated reputation. Below these volumes, shared IPs may offer better protection from insufficient sending activity.
• Warm-up is critical: The process of warming up a new dedicated IP is paramount and requires a strategic, gradual increase in volume to establish trust with ISPs. Failing to do so can severely hinder deliverability.
• Reputation control vs. dilution: A dedicated IP gives full control over one's own reputation, whereas shared IPs dilute individual reputation across many senders. This can be a benefit for smaller senders leveraging good shared pools or a risk if the pool contains spammers.
• Hybrid strategies: Some experts advocate for hybrid approaches, using dedicated IPs for critical transactional mail and shared IPs for marketing, or segmenting based on risk tolerance.
• Monitoring is essential: Regardless of IP type, continuous monitoring of IP and domain reputation via tools like Google Postmaster Tools is crucial for proactive deliverability management.

Key considerations

• Assess current performance: Do not switch to a dedicated IP solely based on assumptions. Analyze current email performance and blocklist status to identify if IP issues are indeed the root cause.
• Commit to consistent sending: If opting for a dedicated IP, be prepared to maintain consistent sending volume and strong engagement. Inconsistent sending can quickly lead to poor reputation and lower inbox rates.
• Understand warm-up process: Allocate sufficient time and resources for the IP warm-up. This process is non-negotiable for building trust with ISPs and ensuring high deliverability.
• Focus on fundamental deliverability: Prioritize elements like good list hygiene, relevant content, and proper authentication (SPF, DKIM, DMARC) over merely changing IP types. As the Mailjet blog notes, these foundational elements significantly impact IP reputation.
• Consider ISP requirements: Be aware that some ISPs have specific requirements or thresholds for recognizing new IPs, making the warm-up process crucial for their filtering systems.

Key findings

• Reputation isolation: Dedicated IPs ensure that your sending reputation is exclusively tied to your sending behavior, preventing external factors from impacting your deliverability.
• Warm-up requirement: New dedicated IPs must undergo a systematic warm-up process, gradually increasing sending volume to build a positive sending history and gain trust with ISPs.
• Shared IP benefits: Shared IPs can offer immediate benefits for new or low-volume senders by allowing them to leverage the established (and hopefully good) reputation of the entire IP pool.
• Volume thresholds: Documentation often suggests that dedicated IPs become more advantageous and manageable for senders consistently sending above a certain volume (e.g., 500,000 to 1 million emails per month), as this volume supports consistent IP activity.
• Risk of blocklisting: On a dedicated IP, a single incident of poor sending (e.g., high spam complaints, spam traps) can lead to immediate and severe blocklisting, as there are no other senders to dilute the negative impact.
• Monitoring is critical: Comprehensive monitoring of IP reputation and engagement metrics is explicitly recommended for dedicated IP users to maintain optimal deliverability.

Key considerations

• Strategic planning: Transitioning to a dedicated IP requires careful strategic planning, not just a technical change, to ensure a smooth warm-up and sustained performance.
• Sender discipline: The onus of maintaining a good reputation on a dedicated IP falls entirely on the sender. Strict adherence to best practices is essential.
• Investment in monitoring: Plan for ongoing monitoring and analysis of deliverability data specific to your dedicated IP. Tools that track DMARC reports and ISP feedback are invaluable.
• Alternative solutions: Consider if addressing list quality, content, or authentication issues might yield greater deliverability improvements than simply changing IP types. As a Klaviyo blog suggests, understanding infrastructure benefits is key.