Summary
Email deliverability and sending speed are multifaceted, influenced by factors spanning technical infrastructure, sender behavior, and recipient engagement. While anecdotal evidence suggests faster delivery to .com domains, experts emphasize that TLD is not the primary driver. Instead, sender reputation, email authentication (SPF, DKIM, DMARC), content quality, and engagement metrics are crucial. Technical aspects like DNS lookup times, server location, and SMTP protocol play a significant role. ISPs and email providers throttle emails from low-reputation senders, impacting speed. Responsible list management, gradual volume ramping, and continuous monitoring via tools like Gmail Postmaster Tools and Microsoft SNDS are essential for sustained deliverability.
Key findings
- Sender Reputation is Paramount: A positive sender reputation, built through engaging content, permission-based marketing, and consistent sending patterns, is the cornerstone of email deliverability.
- Authentication is Essential: Implementing SPF, DKIM, and DMARC authentication protocols is vital for verifying sender identity and preventing spoofing, thereby boosting deliverability.
- Content Matters: High-quality, relevant content that avoids spam triggers is critical for maintaining a good sender reputation and avoiding spam filters.
- Technical Infrastructure Impacts Speed: DNS lookup times, server location relative to recipients, and the efficiency of the SMTP protocol influence email sending speed.
- Throttling Affects Delivery: ISPs and email providers throttle emails from low-reputation senders, limiting the number of emails accepted per connection or timeframe, thus impacting delivery speed.
Key considerations
- Manage Email Lists Responsibly: Practice permission-based marketing, use double opt-in, segment lists for targeted messaging, and provide clear and easy unsubscribe options.
- Monitor and Analyze Metrics: Continuously monitor key metrics like open rates, click-through rates, bounce rates, and spam complaints to identify and address deliverability issues.
- Gradually Ramp Up Volume: Avoid sudden spikes in email volume, especially when starting with a new IP or domain, to prevent triggering spam filters and damaging sender reputation.
- Optimize DNS Settings: Ensure DNS settings are properly configured and utilize a reputable DNS provider to minimize lookup times and improve delivery performance.
- Use Monitoring Tools: Leverage tools like Gmail Postmaster Tools and Microsoft SNDS to monitor sender reputation and troubleshoot delivery issues proactively.
What email marketers say
11 marketer opinions
While some email marketers observe faster sending speeds to .com domains, this is often attributed to factors beyond the TLD itself. Sender reputation, authentication (SPF, DKIM, DMARC), and content quality are crucial. High engagement, clean email lists, double opt-ins, and proper unsubscribe options contribute to a positive sender reputation. Throttling by ISPs, DNS lookup times, and the physical location of sending servers relative to recipient servers also play significant roles in email sending speed. Analyzing per-MX distribution, domain names (especially Gmail and Yahoo), and addressing DNS issues are also key to ensure email deliverability. The quality and reputation of individual domains within a TLD are more impactful than the TLD itself.
Key opinions
- Sender Reputation: A positive sender reputation is critical for email deliverability and sending speed. Factors contributing to this include engaging content, clean email lists, and proper authentication.
- Authentication: Implementing SPF, DKIM, and DMARC authentication protocols is essential to verify the sender's identity and improve deliverability.
- Content Quality: High-quality, relevant content that avoids spam triggers is crucial for maintaining a good sender reputation and avoiding spam filters.
- Throttling: ISPs and email providers may throttle email delivery from senders with low reputation or those sending to high-volume domains, impacting sending speed.
- DNS Impact: DNS lookup times and the reliability of DNS servers can influence email sending speed. Optimizing DNS settings is important.
- Location: The physical location of the sending server relative to the recipient's server can affect sending speed due to network latency.
Key considerations
- List Management: Maintain clean and engaged email lists by using double opt-in, regularly removing inactive subscribers, and providing clear unsubscribe options.
- Engagement Monitoring: Monitor email performance metrics such as open rates, click-through rates, bounce rates, and spam complaints to identify and address deliverability issues.
- Volume Ramping: Avoid sudden spikes in email volume, especially for new senders, as this can trigger spam filters. Gradually increase sending volume over time.
- Per-MX Distribution: Check the distribution of domains in the email list, and focus on optimising the larger domains.
- Domain Analysis: When encountering email delivery delays, check that the domain that email delivery is being sent to has the correct setup.
Marketer view
Email marketer from Reddit states that throttling by ISPs and email providers is a key factor. They mention that large providers like Gmail and Yahoo may limit the number of emails accepted per connection or within a specific timeframe, especially from new or low-reputation senders.
24 Jun 2024 - Reddit
Marketer view
Email marketer from HubSpot explains the factors that impact email deliverability. HubSpot emphasizes the importance of permission-based email marketing, clean email lists, and relevant content to improve deliverability. They suggest using double opt-in, segmenting lists, and personalizing emails to enhance engagement and avoid spam traps.
12 Feb 2024 - HubSpot
What the experts say
5 expert opinions
Experts agree that several factors affect email sending speed and deliverability. DNS lookups, IP address reputation, and sending volume all play crucial roles. Larger email providers respond and accept mail faster than smaller servers. Throttling by mailbox providers, especially for low-reputation senders, slows delivery. Seed testing is also important for measuring deliverability across different domains.
Key opinions
- DNS Latency: DNS lookups for each domain add latency to email sending. Sending multiple messages in a single session helps amortize setup costs.
- IP Reputation: The sending IP address's reputation significantly impacts delivery speed; a poor reputation can lead to throttling or blocking.
- Sending Volume: Sudden spikes in sending volume can trigger spam filters, slowing delivery. A gradual increase in volume is preferable.
- Throttling: Mailbox providers use throttling to control the rate at which they accept emails, especially from low-reputation senders.
- Server Response Time: Larger email providers such as Gmail and Yahoo tend to respond and accept emails faster than smaller servers.
Key considerations
- Monitor IP Reputation: Regularly monitor your sending IP address's reputation to identify and address any issues affecting deliverability.
- Ramp Sending Volume: Gradually increase email sending volume, particularly when starting with a new IP address or domain, to establish a positive sending reputation.
- Implement Seed Testing: Use seed testing to monitor deliverability rates across various mailbox providers and identify potential delivery issues.
- Monitor DNS timeouts: You should be pruning addresses on DNS timeouts or connection failures
- Plan for Throttling: Be aware of throttling mechanisms and plan your sending strategies to accommodate rate limits imposed by mailbox providers.
Expert view
Expert from Word to the Wise (Laura Atkins) explains that throttling is a mechanism used by mailbox providers to control the rate at which they accept emails from a particular sender. Throttling can significantly slow down email delivery, especially for senders with low reputation or those sending to high-volume domains.
31 Aug 2024 - Word to the Wise
Expert view
Expert from Email Geeks explains that DNS lookups for each domain add latency. Sending multiple messages in a session amortizes setup costs for domains with many recipients. Also suggests that Gmail and Yahoo respond and accept mail faster than smaller servers and to check for pruning addresses on DNS timeouts or connection failures.
3 Jan 2022 - Email Geeks
What the documentation says
4 technical articles
Email deliverability is influenced by several factors, as highlighted by various documentation sources. Sender reputation is paramount, with both Gmail and Microsoft emphasizing its impact. Authentication protocols (SPF, DKIM, DMARC) are essential for verifying sender identity. SMTP governs the technical processes of email transfer. Monitoring sender reputation through tools like Gmail Postmaster Tools and Microsoft SNDS, along with managing subscriptions responsibly, is crucial. Engagement metrics, such as bounce rates and spam complaints, need careful attention to maintain a healthy sending reputation.
Key findings
- Sender Reputation: Gmail and Microsoft both emphasize the critical role of sender reputation in ensuring email delivery to their users.
- Authentication: SPF, DKIM, and DMARC protocols are fundamental for authenticating email senders and preventing spoofing, thereby enhancing deliverability.
- SMTP Protocol: RFC 5321 outlines the standard SMTP protocol which governs the technical processes of email transmission, influencing delivery speed and reliability.
- Engagement Metrics: Monitoring bounce rates, spam complaints, and other engagement metrics is essential for assessing and improving sender reputation.
Key considerations
- Use Postmaster Tools: Utilize Gmail Postmaster Tools and Microsoft SNDS to actively monitor sender reputation and identify potential issues affecting deliverability.
- Manage Subscriptions: Implement responsible subscription management practices, including clear opt-in and unsubscribe options, to avoid spam complaints.
- Consistent Sending IPs: Maintain consistent sending IP addresses to help establish a reliable sender reputation.
- Adhere to Best Practices: Adhere to established email marketing best practices to avoid being flagged as spam by receiving mail servers.
Technical article
Documentation from SparkPost shares details regarding all things Email Deliverability. SparkPost outlines the key factors that impact email deliverability, including sender reputation, authentication protocols (SPF, DKIM, DMARC), and engagement metrics. It emphasizes the importance of monitoring bounce rates, spam complaints, and sender score to maintain a healthy sending reputation.
8 Aug 2021 - SparkPost
Technical article
Documentation from Microsoft Docs details how sender reputation impacts email delivery to Outlook.com. It advises on monitoring the Smart Network Data Services (SNDS) to identify and resolve issues affecting sender reputation, such as spam complaints and blocked IP addresses.
13 Aug 2024 - Microsoft Docs
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