Is there a standard format for late bounce error messages and how are asynchronous bounces best handled?
Summary
What email marketers say8Marketer opinions
Email marketer from StackOverflow shares that parsing bounce messages can be complex due to variations in formatting. They recommend using a dedicated bounce processing library or service to handle this task effectively.
Email marketer from SendGrid shares that understanding different bounce types (hard vs. soft) is important for email deliverability. Hard bounces indicate permanent delivery failures, while soft bounces are temporary. SendGrid automatically handles bounce processing and provides analytics on bounce rates.
Email marketer from Email Marketing Forum shares that reducing bounce rates involves implementing double opt-in for email subscriptions and regularly cleaning email lists to remove invalid or inactive addresses.
Email marketer from Mailjet explains that proper bounce management is crucial for maintaining sender reputation. They recommend using VERP (Variable Envelope Return Path) to associate bounces with specific email campaigns and list hygiene to remove bouncing addresses.
Email marketer from SparkPost shares they use VERP and custom headers to capture extra information about the original email which caused the bounce.
Email marketer from Litmus explains that improving email deliverability requires a multi-faceted approach, including email authentication (SPF, DKIM, DMARC), list segmentation, and personalized content to improve engagement.
Email marketer from Reddit shares that VERP is commonly used to track bounces to the originating email address. They also recommend monitoring feedback loops and removing unsubscribed users promptly.
Email marketer from Postmark answers question about asynchronous bounces, and explains that these are delayed bounce messages that can be difficult to track. They recommend using a dedicated IP address and monitoring bounce rates to identify and address deliverability issues.
What the experts say6Expert opinions
Expert from Spam Resource suggests implementing a robust bounce processing system that can automatically categorize bounces (hard vs. soft) and update email lists accordingly to maintain deliverability and sender reputation. They highlight that there is not a single standard, so robust parsing and logic is required.
Expert from Email Geeks suggests VERP is useful, but implementing it today is uncertain due to the rarity of async bounces and the increase of spam targeting VERP return-path addresses.
Expert from Email Geeks mentions RFC3464 as the standard and notes that most ESPs use VERP to connect delayed bounces to the original email/campaign.
Expert from Word to the Wise explains that asynchronous bounces are difficult and messy, especially because the original transaction has completed. They suggest looking at RFC 3464 for delivery status notifications (DSNs) which are the standard way to report bounces.
Expert from Email Geeks explains that mail handlers should avoid sending asynchronous bounces but bulk senders need to handle them as ignoring them may not affect their reputation.
Expert from Email Geeks explains that sending delayed bounces is frowned upon and suggests that time shouldn't be spent on creating a standard for something that shouldn't be done when alternatives exist.
What the documentation says5Technical articles
Documentation from ietf.org explains that RFC 3464 defines a standard format for delivery status notifications (DSNs), which include information about delivery failures, including late bounces. It specifies the structure and content of these notifications to ensure interoperability between different mail systems.
Documentation from AWS explains how Amazon SES handles bounces and complaints. It details how to set up bounce notifications using Amazon SNS and how to track bounce rates using the SES console.
Documentation from Microsoft Learn explains how Exchange server generates non-delivery reports (NDRs) for bounced messages. It also covers the types of information included in these NDRs and how administrators can interpret them to troubleshoot delivery issues.
Documentation from Mailgun Documentation explains that Mailgun uses webhooks to notify users of bounce events, including asynchronous bounces. The documentation details the structure of these webhook payloads, which contain information about the bounced email, such as the recipient, bounce code, and bounce description.
Documentation from Google explains that Postmaster Tools provides insights into your email sending reputation, spam rates, and bounce rates. Using this tool can help identify and resolve deliverability issues.