Deliverability Management

No email service provider’s (ESP’s) capabilities matter if the email doesn’t get through. Getting your email accepted, the first step in getting it delivered to the inbox, is fundamental to what we do. It’s known as deliverability. FeedBlitz’s deliverability is 99.8%.

  • We can and do deliver successfully to internet service providers (ISPs) and domains that other services can't. 
  • We can and do inbox better than other ESPs.

We achieve this through a variety of mechanisms, which, taken together, deliver unparalleled ability to get your emails to where you - and your readership - want them. The recipient’s inbox.

The key to this is reputation, both ours (as an ESP) and yours (as a sender).

This is how we ensure ours, so you can be sure of yours.

To maintain and improve our joint reputations, the following factors matter the most:

All these approaches mean that our servers consistently deliver high-quality mailstreams that you can be confident will get the job done. Your email is surrounded by - and protected by - the millions of emails we send and deliver for corporations like LinkedIn and AT&T; organizations like the US Catholic Council of Bishops; and industry leaders like Seth Godin.

Strict Quality Controls

Nothing ruins a sender reputation more quickly than sending junk mail to junk addresses, so we stop it before it even happens.

Content-wise, we don’t allow you to send a mailing that would trigger our own spam filters. That way, you know that the risk of an email being misrouted thanks to a secondary content filter is very much reduced. Again, this keeps the mailstream quality up.

We correlate new subscribers with our internal lists of known bad addresses and third-party reputation resources to ensure that we are only mailing legitimate subscribers and not sending to trap, stolen or purchased addresses. We look very closely at where new subscriptions are coming from, too.

FeedBlitz also sets and enforces minimum engagement standards larger, active lists. We \actively remove non-engaged list members until these criteria are met.

Finally, we monitor every list's metrics for every client, every fifteen minutes, every day. Any list that deviates from industry best practices is automatically paused while we discuss any issues or concerns with its owner. That way, we ensure that our servers' active mailings remain at the level ISPs love to see and that our metrics are always better than industry best practices. Together, this constant focus on quality greatly increases the likelihood that your email will be accepted and delivered to the inbox.

Reputation Monitoring

Not only do we ensure that all active lists comply with our strict quality metrics, but we also track each of our SMTP servers’ reputations via trusted external vendors. We also test our ability to deliver to leading US and international ISPs every few minutes to ensure that we always take into account their in-house reputation resources. These can be very different - and much more dynamic - than publicly available blacklists (a.k.a. RBLs). They’re also invisible to third-party monitoring services, which is why we use both approaches to ensure we route the mail correctly for you.

These reputation monitors are complemented by tracking our bulk mailing servers’ Sender Scores (Sender Score is an independent third party service that ranks bulk email IP reputation); quality data from Microsoft’s SNDS service; and analytics from Gmail’s postmaster tools.

All of our monitoring comes together with smart routing, which adapts to detected issues (such as throttling or detecting an ISP reputation change) and ensures that email for a domain goes via a server that’s going to have its email accepted by that domain.

It’s Our Sending Infrastructure, Not Someone Else’s SMTP Cloud

Given how vital reputation is to bulk email deliverability success, it may surprise you to learn that many ESPs outsource that to SMTP cloud services. It strikes us as odd that an email service should outsource the most important thing they do. SMTP cloud services can also get very expensive very quickly as you ramp up your mailing volume, as they tend to charge per email sent. (There’s a reason some ESPs charge you more the more you send and then bill you shocking overages. It’s because under the hood, they have someone else’s variable cost infrastructure).

Our IPs aren’t running on someone else’s cloud. Our goal is to win the inbox. To do that, we have to control the core technology (and the IPs) that ultimately deliver the email. That commitment to owning and maintaining our sender reputation at every layer of the app stack is a significant contributor to our ability to getting the mail through to places others cannot.

You might have noticed that we don’t offer dedicated IPs. Here’s why. They are expensive, take time to “warm up” with major ISPs, concentrate your risk on a very small footprint, and are a sign that the ESP involved isn’t managing its shared infrastructure properly (which in and of itself is a risk factor for their domain reputation, even on a dedicated IP range). If you’re having deliverability issues with your ESP, their suggestion that a dedicated IP will magically solve everything is, in our opinion, flat-out wrong.

There’s no magic solution to poor deliverability - and if there were one, it certainly wouldn’t be a case of doing the same old same old with a shiny new IP address. It is practices and policies that drive a sending IP’s reputation, not the other way around.

If this situation is you and your ESP, we would be more than happy to prove that we can get emails to any domains you’re having issues with. No dedicated IP required.

By contrast, because of how we manage our lists, mailings, subscribers and reputation, your email is going to be at the same quality level from day one as all our other clients’ (i.e. excellent). Because we are so rigorous about quality, your mail is protected by the other very high-quality clients and mailings we support; and your high-quality mailings help protect everyone else’s. It’s a virtuous cycle positive feedback loop. Unlike other ESPs, we love it when our clients email more because we know each and every quality send is further enhancing our reputation.

As a result, we don’t and won’t throttle you (nor do we have overages because our SMTP infrastructure is a fixed cost). If your readers want to hear from you, we’re delighted to help you contact them - even if you’re mailing over a half million people two or three times a day (seriously - we have clients who do this, very successfully, daily).

Subscriber Management Policies and Practices

It is a core value of ours that control of a subscription belongs with the subscriber, and that their being on a mailing list is a privilege they can revoke at any time from anyone.

The ISPs track their users’ reactions to, and engagement with, your mailings. To ensure that ISPs see your mailings as the best quality possible (and to keep your workload down), we manage all subscribers and readers for you as follows:

  • Hard bounces, unsubscribe requests, and Feedback Loop (FBL)* notifications are all processed immediately. 
  • Soft bounces that persist for more than three instances over two weeks are removed.
  • While single opt-in is available, it is a privilege that is earned after an account has established its mailing history.
  • Dual opt-in is the default subscription mechanism, and mandatory for jurisdictions where privacy rules (e.g. GDPR) are applied.
  • We apply rules and filters to stop both spambots and manually created junk from being added to your lists.
  • We do not allow role accounts (e.g. info@) onto lists.

*A feedback loop (FBL) is a mechanism where an ISP (e.g. Gmail) or an email app (e.g. Apple Mail on an iPhone) sends an unsubscribe request to a bulk email service provider (ESP - in this case, FeedBlitz) when the email is considered to be spam or otherwise unwanted by the recipient. FBL requests are tracked separately from regular unsubscribes; an FBL notification is known as a “complaint.” The complaint rate is a critical mailing metric and must be kept very low (the industry standard is <0.1%). FeedBlitz is on the FBLs for all major US and international ISPs.


We authenticate all email we send using SPF and DKIM, organized with a supporting DMARC policy. We strongly recommend delegating authority to us in your SPF and DKIM settings (our support team can help you, and enterprise clients have significantly more control over their domains when they delegate authentication).

You Win The Inbox, We do the Work

All of these policies, standards and procedures have evolved over the years. They work, especially in the contemporary email environment where spam, phishing attacks, and other forms of email abuse make it increasingly difficult to get legitimate bulk marketing emails (i.e. your mailings to your lists) through.

We succeed.

We succeed because we coerce best practices onto every client, list, subscriber, and mailing.

And so?

We get your email accepted at higher rates than anyone else we know.

Let us prove it to you.

As always, if you have any questions, please don't hesitate to let us know. You can find all of our great support resources and how to get in touch with us via email, chat, or phone on our Support Page.

Did you find it helpful? Yes No

Send feedback
Sorry we couldn't be helpful. Help us improve this article with your feedback.