Email is still one of the most effective and widely used marketing channels, which is why I’m excited to share some important updates about our bounce-handling logic. These changes are designed to help you maintain exceptional email deliverability, keep your domain reputation strong, and continue to build lasting relationships with your contacts. As an email deliverability specialist with over a decade of experience, I know how crucial it is to balance robust bounce rules with the realities of ever-changing inbox conditions.
In this blog, I’ll outline our new unified approach to handling consecutive soft bounces across all email providers, describe how it addresses current challenges, and offer some insights into how you can customize these rules to fit your unique needs.
The Challenge: Gmail and Full Inboxes
One of the most prevalent issues we’re seeing, especially with Gmail users, is the dreaded “full inbox/full drive” scenario. Google’s more stringent soft bounce rules, which have been recently updated, mean that users who haven’t cleared their storage or inbox can suddenly find themselves unable to receive messages. In the past, these soft bounces would quickly get flagged and sometimes lead to premature permanent suppressions — even though many of these inboxes would free up in a matter of days or weeks.
Why It Matters
- Deliverability risks: Sending repeated messages to addresses bouncing due to full inboxes can harm your sender reputation
- User frustration: Contacts who clean up their inbox may not realize they’ve been permanently suppressed on your list
- Gmail’s strict guidelines: Gmail pays close attention to bounce rates, so managing these bounces properly is key to maintaining a strong domain reputation and achieving high inbox placement
The Old Logic
Previously, our platform had a somewhat opaque set of rules that were only consistently applied to Mailgun. With Mailgun, if an address had three consecutive soft bounces in seven days or five consecutive soft bounces over any timeframe, it led to a temporary suppression for seven days.
After this temporary suppression, a single subsequent soft bounce would result in a permanent suppression. These rules primarily applied to Mailgun. Other providers weren’t subject to the same logic, causing confusion and uneven deliverability strategies. Additionally, because Gmail accounts might not free up in under a week, a permanent suppression after 7 days might be too aggressive.
Why This Was Problematic
- Inconsistency: Having different bounce rules for different providers led to confusion for both our team and our clients
- Limited customization: Our previous approach didn’t let clients fine-tune how many bounces triggered a suppression or how long the suppression lasted
- Premature permanent bounces: Some users who had fixed their inbox issues were being permanently suppressed
Our New, Unified Approach
We’re excited to announce a new solution that standardizes the bounce logic across all providers (while still honoring certain Mailgun-specific error codes):
Applied to All Providers
The same cumulative bounce logic will now apply across the board, simplifying how you interpret your bounce statistics.
For Mailgun, we’ll continue to exempt error code 602 from the cumulative bounce logic. We’ve found through extensive data analysis that 602 indicates a unique scenario requiring a separate approach.
The New Cumulative Bounce Logic
Stage 1: If there are three consecutive soft bounces, the address is temporarily suppressed for 14 days.
Any time a profile receives a campaign event with status delivered or revalidated, the cumulative bounce logic is restarted (i.e., three consecutive soft bounces mean there has not been any delivered/revalidated status between them).
Stage 2: Once the suppression is lifted and the address bounces three more consecutive times, it’s temporarily suppressed again for another 14 days.
Stage 3: If, after that second temporary suppression, the address soft bounces even once, it will be permanently suppressed.
In effect, we’re adding an extra round of temporary suppression, and each round lasts longer (14 days) than before. This means a contact has up to 30 days total to address their inbox issues before the system opts for permanent suppression — an approach that’s far more flexible for those with periodic Gmail storage complications.
Why This Is Better
- Greater flexibility: By allowing for multiple rounds of temporary suppression, we accommodate users who might fix their inbox issues over time
- Improved deliverability: This balanced system keeps you from repeatedly mailing dead addresses while also avoiding unnecessary permanent suppression
- Unified rules: No more guesswork about which rules apply to which provider — everyone is on the same page
Customization: A New Level of Control
To further empower you, we’re rolling out customizable settings so you can tailor the bounce logic to your audience’s behavior:
Adjustable Parameters
- Number of soft bounces leading to temporary suppression: The default is 3, but if you see a pattern in your bounce data you can consult changing this parameter with your consultant or email specialist. We suggest keeping this at the default value of 3 for optimal results.
- Length of temporary suppression: The default is 14 days, but you’ll be able to extend or shorten this period to align with your sending cadence.
Please note that the soft bounces setting will be accessible for modifications only to internal users with a @bloomreach address. While all users will be able to view the value, only internal users will have the ability to change it. This approach reflects our strong preference for maintaining the value at 3, as we believe it aligns best with recommended practices. However, we recognize that clients may have valid reasons for adjustments, so we’ve provided the flexibility to modify it when necessary.
Access and Visibility
- Project settings: You’ll find these controls under the new “Bounce Management” section in your project settings (exact naming may vary based on the final UI).
- Internal vs. client control: While the temporary suppression length is open for you to modify directly, the number of bounces leading to suppression is visible but changeable only by our internal support or deliverability specialists. We want to ensure these parameters aren’t set too high or too low without expert guidance.
Aiming for 99.5% Deliverability — and Beyond
Our goal is to help you achieve a 99.5% deliverability rate (or better) while also striving for the 99% inbox placement club. These new rules:
- Protect your domain reputation: By reducing reckless repeat sends to known bad addresses, you’ll maintain a positive sender score and domain reputation
- Keep clients informed: The more transparent, uniform, and customizable your bounce rules are, the better you can communicate potential issues to your end users
- Align with best practices: The extended temporary suppression approach is in line with top-tier deliverability standards and helps to future-proof your sending strategy as mailbox providers continue to evolve
Ultimately, by enhancing our cumulative bounce logic, applying a consistent approach across all providers, and introducing customizable settings, we’re confident that these changes will lead to stronger deliverability, improved domain reputation, and better relationships with your subscribers. We’re committed to being a thought leader in this space and invite you to reach out with any questions, concerns, or custom requests.
Here’s to hitting that 99.5% deliverability mark — and welcoming you into the 99% inbox placement club!
As always, if you have any questions, don’t hesitate to contact our support team or your dedicated deliverability specialist.
Happy sending!
