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How does Bounce Shield work?
How does Bounce Shield work?

Bounce Shield is our system that protects your deliverability by stopping sending process before the provider's limit is reached.

Weronika Wróblewska avatar
Written by Weronika Wróblewska
Updated over a week ago


Notification about active Bounce Shield

Email providers set daily, sometimes even hourly, limits for sent and received emails. (Check the sending limits of different email providers.) Exceeding these limits risks your email account being blocked without warning, potentially harming your campaign's success. By using Bounce Shield, you can reduce the chance of account blocks by 59%.

How it works

Bounce Shield is our system that works in the background while your emails are being sent. You do not need to turn it on as it constantly monitors your campaigns.

We implemented it to help you protect your deliverability and avoid reaching your provider's send quota, which could result in a 24-hour block.

As soon as our system detects that your sending volume is about to reach the limits of your provider, we lower the sending volume of your emails by 50% for 24 hours or by 10% for 10 days. After this time, an attempt will be made to return to the original sending parameters.

Notfication displaying "You've reached your provider's sending limit"

What does it protect me from?

In general, it helps to maintain good deliverability by keeping your sending below your provider's limit.

This way, you avoid being blocked by your provider (which would stop your sending for the entire day) and have a better chance of having and keeping a good reputation as a sender.

It does not protect you from receiving bounces, as you still need to remember to prepare your domain and email account with the warm-up process for sending.

After that, you should take some time to create a well-written and personalized email copy in order to avoid the spam folders of your prospects.

Bounce Shield isn't designed to hold back your email sending potential. It monitors how many emails you’ve sent on a given day and helps you stay within your provider's limit. This action prevents you from potential deliverability drops caused by sending over-limit emails that never reach prospects' inboxes. Think of it as your sidekick, keeping your sender reputation strong and making sure your emails reach their destination.

Email deliverability – good practices

Learn how to create and schedule cold emails that get delivered straight to your prospect’s inbox – read our free guide »

What benefits does Bounce Shield bring to your inbox?

Since early 2022, we've identified inboxes that were blocked for surpassing their provider's limits. From this data, we compared 1300 inboxes using Bounce Shield to over 1600 without it. The difference in received inbox blocks was 7674 — that’s 2.4 times fewer blocks for inboxes with Bounce Shield protection.

Below is the comparison chart with data pulled from our system, how the sending from one account over 15 days looks like when Bounce Shield is turned off and on – the absence of data on the graph on a given day means that the sending quota for the previous day was exceeded. Your email provider stopped the ability to send from the mailbox altogether for 24 hours. The number of emails sent out during this period with Bounce Shield disabled is 14,440.

As for the green color on the chart, it shows the data of sending with the Bounce Shield turned on. On a day previously blocked from sending (and marked as "quota exceeded error"), everything is kept on schedule thanks to Bounce Shield's quick response. This mechanism allows sending to continue but in smaller quantities, so there are no interruptions in the process. The total number of messages sent during this period is 15,910 – so even when sending less with Bounce Shield, more messages will be sent for a longer period.

The impact on campaign flow

Inboxes relying on Bounce Shield maintain a steady campaign flow and quickly adjust to new limits to prevent interruptions. In contrast, inboxes operating without Bounce Shield and ignoring their provider's limits may send more emails in a day, but frequent exceedances result in their campaigns being paused for 24 hours, wasting potential sending days.

The best way is to keep a balance between short-term gain and long-term loss. Following Bounce Shield's recommended daily email count places your inbox on the safe side, ensuring a consistent email flow, rather than risking a halt in sending the next day.


Q.: I want to send more emails. Can I turn it off?

Bounce Shield can be turned off, but we recommend keeping it enabled. This mechanism protects your sending, so you don't get risked being blocked by your email provider.

Q.: Why am I still receiving bounces?

Please, check our section on What does it protect me from? If you want to work on your deliverability, here’s our article on How to lower my bounce rate? »

Q.: How much does it cost?

Bounce shield is free to all of our users, and it doesn’t need to be turned on/purchased in order to be active.

Q.: What are my provider’s limits?

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