How to synchronize unsubscribes between two ESPs during migration?
Summary
What email marketers say8Marketer opinions
Email marketer from Litmus recommends using List-Unsubscribe headers. These headers allow recipients to unsubscribe directly from their email client, and the unsubscribes can be managed and propagated across different ESPs via a central system.
Marketer from Email Geeks shares a solution involving a master subscriber list on ESP1, periodic syncing with ESP2 via API, and updating the master list based on unsubscribes from either platform. ESP2 needs to trigger something based on an unsubscribe, or use an unsubscribe notification email parse.
Email marketer from Email on Acid shares that a central unsubscribe management system is critical. This system should receive unsubscribe requests from all ESPs and update all lists accordingly in a timely manner.
Email marketer from Reddit suggests implementing a shared database to keep track of unsubscribes, which is then accessed via API by all ESPs that you use. This database then acts as your single source of truth.
Marketer from Email Geeks suggests replacing the unsubscribe link with an email address as a low-tech workaround.
Email marketer from Neil Patel shares that maintaining a clean email list is crucial for deliverability. Implementing a double opt-in process and regularly removing inactive subscribers can help ensure that your list is up-to-date and reduces the risk of sending to addresses that have unsubscribed on another platform.
Email marketer from EmailVendorForum answers to create a custom solution to sync unsubscribes. Create API endpoints to handle subscribe/unsubscribe requests from both ESPs, and have each ESP make API calls to your solution whenever a user updates their subscription preferences.
Email marketer from StackOverflow answers about subscribing to multiple ESP unsubscribe notifcations, and creating an internal process to keep all lists in sync. However, the advice is the user should use 1 ESP.
What the experts say3Expert opinions
Expert from Word to the Wise suggests implementing robust Feedback Loops (FBLs) and utilizing them to track unsubscribe requests. Monitor FBL data from all participating ISPs, process the data to identify unsubscribed users, and then synchronize these updates across your ESPs.
Expert from Email Geeks suggests synchronizing unsubscribes via backend APIs or list upload/download for reliability and easier error correction. Scripted batch processing a few times a day is recommended.
Expert from Spam Resource recommends building a central unsubscribe processing system that all email sending platforms can access. This involves creating an API endpoint to handle unsubscribe requests and ensuring that all systems update the central list when an unsubscribe occurs.
What the documentation says4Technical articles
Documentation from SendGrid explains that they offer a Global Unsubscribe Group that can be used to manage recipients. When a recipient unsubscribes from this group, their email address is added to a suppression list. The API can be used to keep multiple lists in sync.
Documentation from Amazon Web Services explains that Amazon SES provides mechanisms for handling bounces and complaints, which can be used to maintain a clean subscriber list across different ESPs during migration. They recommend setting up notifications and using the data to update unsubscribe lists on both platforms.
Documentation from Mailgun explains that Mailgun offers webhooks that trigger when a user unsubscribes. By subscribing to the 'unsubscribe' webhook, you can automatically update the unsubscribe list on your other ESP in real-time.
Documentation from Google answers about setting up feedback loops and unsubscribe headers. You will be automatically unsubscribed by Gmail if you fail to meet their email guidelines.