CloudMailin monitors the health of your outbound email to maximise deliverability and protect your sending reputation. Every outbound message passes through a series of checks before it leaves our servers — because if the receiving mail server is going to check, it's better to catch problems before they affect your reputation.
This page explains what we monitor, why, and how you can maintain a healthy sending account.
Email providers like Gmail, Outlook and Yahoo continuously evaluate sender reputation. They look at signals like bounce rates, spam complaints and engagement (opens, clicks) to decide whether your emails reach the inbox or land in the junk folder.
A single sender with poor practices can damage the reputation of the shared sending infrastructure, affecting deliverability for everyone. CloudMailin's health system is designed to catch problems early — both to protect your deliverability and to maintain the reputation of the platform as a whole.
Every outbound account has a health score between 0 and 100, visible in your dashboard. The score is calculated from a combination of factors including delivery rates, bounce rates, spam complaints and engagement metrics.
| Score Range | Status | Meaning |
|---|---|---|
| 90–100 | Healthy | Your email is performing well. |
| 75–89 | Warning | Some metrics need attention. You'll receive a notification. |
| Below 75 | Danger | Significant issues that need addressing urgently. |
| Below 50 | Critical | Sending may be suspended until issues are resolved. |
Health scores are recalculated regularly. If your score drops, you'll receive an email notification with specific guidance on what to improve.
All outbound messages are scanned for spam characteristics before sending. Messages that
score above our threshold are rejected and you'll receive a suppressed
webhook event.
This is the same kind of content analysis that receiving mail servers perform. By catching it first, we prevent your messages from being silently filtered or penalised by the recipient's mail provider. If we allowed high-scoring messages through, it would damage the sending reputation of the IP addresses used by all CloudMailin customers.
Hard bounces (permanent delivery failures) are tracked against your sending volume. ISPs treat high bounce rates as a strong signal that a sender isn't maintaining clean recipient lists — which is a hallmark of spammers.
Because CloudMailin is for transactional email sent to known, valid recipients, bounce rates should naturally be very low. We expect rates to stay below 2%. Persistent high bounce rates will affect your health score and may lead to account suspension.
You should monitor bounce webhook events and take action promptly — for example, by removing addresses that repeatedly bounce.
When a recipient marks your email as spam, CloudMailin is notified. Even very small complaint rates are serious — ISPs weight complaints heavily when evaluating sender reputation.
CloudMailin monitors complaint rates and will alert you if they rise above acceptable levels. High complaint rates will significantly impact your health score.
CloudMailin adds a small tracking pixel to HTML emails to detect when they are opened. This serves two purposes:
open
webhook events so you can monitor engagement
with your emails.Open tracking only works with HTML emails and depends on the recipient's email client loading images, so it's not 100% accurate — but it's a useful indicator of overall trends.
Open tracking is enabled by default. See Disabling Tracking below if you need to turn it off.
Links in HTML emails are rewritten to pass through a redirect that logs the click before sending the recipient to the original destination URL. The original URL is preserved and the redirect happens transparently.
Click tracking provides engagement data that both you and CloudMailin use to assess email health:
click
webhook events including which link was clicked.Click tracking is enabled by default. See Disabling Tracking below if you need to turn it off.
You can request to disable open tracking, click tracking, or both by contacting support. Before doing so, be aware of the trade-offs:
open and/or click
webhook events.Spam checking and bounce monitoring cannot be disabled — these protect the shared sending infrastructure and are essential for maintaining deliverability across the platform.
If you have questions about your health score or deliverability, please contact us and we'll be happy to help.