In New York, as in most large cities, there are only a fortunate few that live alone. Rent keeps increasing by the day and spacious apartments are hard to come by, so we live with roommates. Sharing an apartment with someone means sharing less favorable habits; dishes left in the sink, waking up at dawn to do Pilates in the living room … but it also means a lower financial burden and responsibility of maintaining the place.

The same kind of consideration goes for IP addresses. You can either share an IP address or buy your own – neither is better than the other, there are pros and cons to both. This Flight School Friday, we’ll explore the two options and help you determine which one works best for your business.

What does this have to do with email?

Similar to roommates, when it comes to sharing an IP address, you’re in it together. Each sender’s reputation on the IP address will affect the others. If you’re just starting off with sending email campaigns or you send a low volume of email, sharing an IP address is a great solution to quickly establish credibility with ISPs such as Google, AOL and Yahoo. At the risk of taking this metaphor too far: this is the same concept as using a guarantor for your apartment if your rent or credit history isn’t established enough.

ISPs will look for consistent sending volume and consistent implementation of email best practices to determine your sender reputation. If your business sends email on a seasonal basis or only needs to communicate occasionally, sharing an IP address is a good way to share the reputation of more established senders. It’s also typically the less expensive option, since you don’t have to pay additional set up fees for an individual IP address.

The downside here is that you’re sharing the reputation of other senders. If these senders forget to clean their contact lists, send an email that falls into a spam trap, use a sensational subject line or any of these black-hat practices, that damages your reputation as well.

Should I get a dedicated or shared IP?

As your business grows and you send larger volumes of email, you’ll likely want to consider moving onto an individual IP address. The reputation of this fresh IP address will be as good or as bad as your sending practices warrant. This means slightly more responsibility than a shared IP address, so you’ll want to make sure you’ve read up on your deliverability best practices and CAN-SPAM law, and of course GDPR.


Working off of your own IP address also makes it easier to track down and troubleshoot deliverability issues. You can even take your campaigns one step further by dedicating an IP address to marketing emails (newsletters, promotional messages) and transactional emails (triggered messages such as thank you emails, birthday emails and reactivation emails).

Marketing emails, due to their promotional nature, are more likely to be marked as spam or generate unsubscribes and bounces. While transactional emails tend to be more used to generate responses like invoices, with password resets and tailored information in response to an action taken by a customer. Separating your traffic onto two separate IP addresses ensures that more crucial transactional emails such as invoices and account updates are not affected by the reputation of your marketing emails.

At the end of the day, there’s really no right or wrong answer here – it’s simply a matter of what your business goals are and how your customers prefer to communicate. We do encourage customers to use a dedicated IP address if they can, to have full reign over their deliverability needs and sender reputation.

But most likely, you’ll get a chance to use both shared and dedicated IP addresses during different stages of your business and for various types of email campaigns. The key takeaway is to do regular maintenance on your IP address, monitor your sender score and review your deliverability reports.