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Marketing • Feb 12th, 2020 • John Paterson

What Is Sender Reputation And How to Improve It?

Understand and maintain your sender reputation to ensure your bulk emails get through and not end up in your customer’s spam folder.

Understanding Sender Reputation

If you want your bulk emails and newsletters to get through and not end up in your customer’s spam folder, then you need to understand and maintain your sender reputation.

Sender reputation is a score that ESPs (Email Service Providers – the companies that provide connectivity and often manage people’s email) give you as a sender of mass emails. It is calculated based on your bounce rate, how many people flag your email as spam and how many people unsubscribe.

If you have a good sender reputation, your emails will arrive safely in people’s inboxes. Conversely, a bad sender reputation will see your emails flagged as spam or, at worst, simply discarded before reaching the recipient. It will also affect the speed that email marketing software like ours will deliver your emails – a bad sender reputation will result in your email delivery rate being throttled back.

Sender Reputation Overview

The key thing about sending out marketing emails is being a good sender. Your Sender Reputation is incredibly important when it comes to the deliverability of your emails and if your customers aren’t receiving your emails then they’re not worth the bytes they’re made of!

An important point here is that you’re sending to your ‘customers’. These are people that will be expecting to receive emails from you and will accept them and be interested in what you have to say.

The fastest way to end up in people's junk files and to get a bad reputation is to send unsolicited emails. That would be mailing addresses you’ve bought on a list or have never had any contact with before. You’ll get so much more from a smaller list of interested subscribers who genuinely want to know what you have to say and sell. You might find our Sales & Marketing article on Email Marketing useful.

The mail servers receiving your emails will be set up to separate good emails from bad and will increasingly base their decision on your sender's reputation, along with the content of the message. A good reputation will be decided by how many unsubscribes, bounces (address that doesn’t exist) and actual spam complaints you get. The less you get and the more people who happily receive your message, and even click through to further content, the better.

Hourly Send Quota

One important factor of email deliverability is the rate at which emails are sent at. The right balance needs to be maintained between getting a large volume of messages out in a reasonable time and not looking like a spammer. Using SpotlerCRM marketing tool, we’ll start you off with a moderate quota of 250 emails per hour then quickly adjust that based on your sender reputation.

If you have a good reputation then mail servers will happily receive your emails and won’t treat a high sending volume with suspicion. That will allow us to increase your hourly sending quota and get your emails out to your customers quickly. You could be sending 20,000 per hour in no time!

A bad reputation will cause high send volumes to be treated more suspiciously and we may have to reduce your quota down low to try and maintain deliverability.

How Sender Reputation is Calculated

Each mailbox provider will have slightly different rules, that they (and we) will take into account:


Lots of bounces means that either you’ve bought a list or you haven’t cleaned your mailing list for a while. So don’t buy email lists and make sure you keep your list clean by not sending emails to addresses that have already bounced. Our Marketing tool handles bounces for you, of course.


Getting flagged as spam by recipients is the worst thing that can happen to your sender reputation. Don’t send emails to people who haven’t asked for them. That means NO purchased lists (no, not even “permission based double opt-in”, when they get your email they’ll hit the spam button). Honour unsubscribes quickly and don’t ever email them again. And if you can, dribble your email campaign out over a few days, or even weeks, to reduce the number of identical emails hitting the same mail provider (like Google) at once


Lots of clickthroughs are good, it shows that recipients like your newsletter. No clickthroughs means that it is uninteresting, so could be spam. So make sure you include some links of interest.

How to Get and Maintain a Good Sender Reputation

Start by sending out small email campaigns, maybe to only a few hundred recipients. That will allow the ESPs time to see that your emails are good

Make sure your list is clean by using it regularly and clearing out bounces

Never, ever, send emails to people who you don’t already have a relationship with

If you are sending 10k or more emails per month it’s worth adding DKIM and SPF entries to your domain’s DNS settings

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