What are prefetch and proxy opens and what causes a decrease in email open rates?
Summary
What email marketers say10Marketer opinions
Email marketer from Sendinblue shares that to improve open rates, marketers should focus on crafting compelling subject lines, segmenting their audience for relevant content, cleaning their email lists regularly, and optimizing send times.
Email marketer from Email Geeks defines prefetch opens as happening during email delivery, not necessarily when the user opens it. Proxy opens mask user device and location details and can happen when the user opens the email or during prefetch. Usually both are proxied.
Email marketer from Litmus shares that MPP inflates open rates by pre-fetching images. This makes it difficult to accurately track engagement based on opens, as many 'opens' are actually automated pre-fetches.
Email marketer from ZeroBounce shares that regularly cleaning your email list by removing invalid and inactive addresses is crucial for maintaining high deliverability and open rates. Reduces bounce rates and improves sender reputation.
Email marketer from HubSpot responds that reasons for low open rates include poor subject lines, irrelevant content, being marked as spam, low sender reputation, and inactive subscribers. Analyzing these factors can help identify the root cause.
Email marketer from Neil Patel explains that personalization, segmentation, and compelling subject lines are essential for boosting email open rates. Tailoring content to specific audience segments increases engagement.
Email marketer from ActiveCampaign shares that email marketing trends include increased personalization, automation, and the use of AI. Adapting to these trends can improve engagement and open rates.
Email marketer from Reddit responds that a sudden drop in open rates could indicate your emails are being marked as spam more often. Check your sender reputation and review your email content for spam triggers.
Email marketer from Reddit suggests that a significant decline in open rates might be due to Apple's Mail Privacy Protection. It inflates open rates but doesn't necessarily mean real engagement is up. Focus on click-through rates for a more accurate picture.
Email marketer from EmailToolTester explains that several factors can affect open rates, including subject line relevance, sender reputation, timing of the email, and list quality. A sudden decrease might indicate deliverability issues or changes in recipient behavior.
What the experts say7Expert opinions
Expert from Word to the Wise shares that factors such as Apple's Mail Privacy Protection (MPP), aggressive prefetching by security software, and the increasing use of bot detection services significantly distort open rates, making them less reliable as an engagement metric.
Expert from Email Geeks explains that pre-fetch happens when the email client builds the message for display between delivery and the user viewing the message on their device. Pre-fetching can happen multiple times for users who use multiple devices. Proxies hide the individual location of a user (and possibly the device details).
Expert from Spam Resource explains that email open rates are generally determined by whether images load in the email. Because many spammers block image loads, there is a disproportionate impact on open rate of legitimate vs spam emails
Expert from Email Geeks explains that an open can be prefetched, proxied, or both. A pre-fetched open is a non-human-interaction (NHI) open where the image is retrieved by automation before the user sees the email, implying the mail client won’t fetch it again. A proxied open is where another system (the proxy) fetches the image on behalf of the client, masking the IP address and browser metadata. Systems often use both prefetches and proxies to obscure user data.
Expert from Word to the Wise explains that a high percentage of opens within 10 seconds of delivery suggests bot activity. These opens often indicate prefetching or security scans rather than genuine user engagement.
Expert from Email Geeks responds that a fast change in open rates while click rates remain steady could be due to ESP changes in reporting or an actual change in recipient behavior. It might not be a cause for panic, but it's worth investigating.
Expert from Email Geeks shares that breaking down opens by mailbox provider can often answer the question of decreased open rates. Changes might be specific to Google (promo tab placement) or Apple (proxy glitches).
What the documentation says5Technical articles
Documentation from DKIM explains that DKIM (DomainKeys Identified Mail) is an email authentication technique that allows the receiver to verify that an email was sent and authorized by the owner of the domain. It uses cryptographic signatures to provide assurance.
Documentation from Mailchimp details that factors influencing deliverability include authentication (SPF, DKIM, DMARC), sender reputation, content quality, and engagement. Poor deliverability directly impacts open rates as emails land in spam folders.
Documentation from Apple Developer Documentation explains that Mail Privacy Protection (MPP) hides a user’s IP address so it can’t be linked to other online activity or used to determine their location. Also prevents senders from knowing if an email has been opened.
Documentation from RFC explains that SPF (Sender Policy Framework) is an email authentication method designed to detect forging sender addresses during the delivery of email. Specifies the mail servers allowed to send mail on behalf of your domain.
Documentation from DMARC explains that DMARC (Domain-based Message Authentication, Reporting & Conformance) is an email authentication protocol that builds on SPF and DKIM to provide domain-level protection against email spoofing. Allows senders to indicate that their emails are protected by SPF and DKIM and tells receivers what to do if authentication fails.