How do HTML email size, TLD, attachments, and domain reputation affect deliverability and open rates?
Summary
What email marketers say10Marketer opinions
Email marketer from Quora emphasises that smaller email sizes are vital for mobile users. Large emails can take longer to load, leading to decreased engagement, especially for users with limited data or slow connections.
Email marketer from Neil Patel answers that older domains with established sending histories often have better reputations. Building a positive sending history takes time, which can improve deliverability rates compared to newer domains.
Email marketer from Email Geeks explains that switching the domain from fr/de to .com can impact deliverability if the .com domain isn't properly warmed up and doesn't have a good reputation. Also people might be using inbox filters for the fr/de domain.
Email marketer from Email Marketing Forum shares that using a reputable TLD (like .com, .net, or .org) is generally recommended. Less common or suspicious TLDs might raise flags with spam filters.
Email marketer from Sender responds that a positive sender reputation is crucial for email deliverability. Factors contributing to sender reputation include sending volume, bounce rates, spam complaints, and engagement. Poor reputation can lead to emails being filtered as spam.
Email marketer from Stack Overflow discusses how using inline CSS is crucial for HTML emails, as many email clients strip out or ignore linked stylesheets. Using proper and supported CSS ensures the email renders correctly, affecting engagement and deliverability positively.
Email marketer from Mailjet shares that larger HTML email sizes can negatively impact deliverability. Larger emails take longer to load, which can frustrate recipients and lead to lower engagement, potentially harming sender reputation.
Email marketer from EmailGeeksForum.net shares that using country-specific TLDs (like .de for Germany or .fr for France) can improve deliverability in those regions because they appear more familiar and trustworthy to local recipients.
Email marketer from Litmus shares that poorly coded HTML can affect email deliverability. Clean, well-structured code improves rendering across different email clients and reduces the likelihood of being flagged as spam.
Email marketer from Reddit user u/EmailExpert explains that sender reputation is critical. If your domain is new, start with low volume, closely monitor bounce rates and spam complaints, and gradually increase volume. Consistent, positive engagement builds reputation over time.
What the experts say7Expert opinions
Expert from Email Geeks shares that the TLD (e.g., .com, .de) should have a negligible effect on deliverability, assuming it's a legitimate TLD. While using a local geoTLD might have marketing benefits for branding, a .com is generally acceptable worldwide.
Expert from Email Geeks responds that if open rates have dropped more significantly on Hotmail/Outlook and GMX, the reason could be the mail going to bulk. He then advises that there are many things that could have changed and image load rates on their own are not enough to action anything from.
Expert from Email Geeks recommends looking at open rates broken down by MX or recipient domain to diagnose sending issues. Changes in open rates at a specific ISP can provide more actionable insights than overall open rates.
Expert from Word to the Wise (Laura Atkins) explains that newer domains often face deliverability challenges due to a lack of established reputation. Building a positive reputation over time is essential for improving deliverability rates.
Expert from Spamresource highlights that sending attachments can negatively affect sender reputation if abused. Sending unsolicited attachments or attachments that trigger spam filters can lead to blacklisting and reduced deliverability.
Expert from Email Geeks explains that the size of the HTML email due to conditional blocks shouldn't impact open rates, as the ESP executes the conditional logic and only sends one block. He suggests other factors might be causing the fluctuation in image loads.
Expert from Email Geeks suggests attaching a shipping label as a PDF can affect deliverability. Attached files increase email size, potentially interfering with image loads at Google and triggering spam filters.
What the documentation says5Technical articles
Documentation from Spamhaus explains maintaining a clean IP reputation is crucial for deliverability. Blacklisting on services like Spamhaus can severely impact deliverability, so it's important to monitor and address any issues promptly.
Documentation from RFC Editor specifies the technical standards for email, stating that the TLD (Top-Level Domain) should be valid and properly configured to ensure correct routing and deliverability. Invalid or misconfigured TLDs can lead to email rejection.
Documentation from Google Workspace Admin Help explains that Gmail has attachment size limits that can impact deliverability. Exceeding these limits can cause emails to be rejected or marked as spam.
Documentation from DKIM.org explains that implementing email authentication methods like DKIM, SPF, and DMARC helps improve deliverability. These methods verify the sender's identity and reduce the likelihood of emails being spoofed or marked as spam.
Documentation from Microsoft Support explains that certain attachment types are more likely to be flagged as spam. Executable files (.exe), scripts, and other potentially harmful file types can trigger spam filters, affecting deliverability.