Running bulk mail through our own SMTP server or using a service like Sendgrid or MailChimp

Question

We are a small company that typically sends out < 10,000 emails each month. We have a new client (an extremely large multinational corporation) that wants us to email a portion of their customer base (just under 100,000) on their behalf. These are people who agreed to receive email.

As we haven't had to send that much email before, we're wondering if we should send it ourselves or use a service like Sendgrid or Mailchimp.

Our initial test, however, resulted in a bounce rate of 15%, which is fairly high. I believe that this would result in us being banned by Sendgrid or Mailchimp.

So if that is not an option, we will send them ourselves. But if we suddenly start sending out 100,000 emails in the course of a day or two, will we be pegged as spammers?

Answer 1

There are two schools of thought on this and for the sake of openess I will discuss both.

Run Your Own SMTP Server
By running your own SMTP server for sending these emails you will not have any issues with being banned for a high bounce rate or being limited to a certain number of emails each month. The downside of this is that it is easy to wind up with your IP being blacklisted and a lot harder if you don't have a reasonable amount of experience in de-blacklisting your IP's that your domains and IP''s will stay blacklisted which will result in even less emails being delivered.

Use a Mail Delivery Service
Email delivery services are good as that is all that they do. They have large pools of IP's that they can use to send emails from and have the infrastructure to handle sending a huge amount of emails at any given moment in time. In addition if SPAM reports start to become an issue they will generally work with you to deal with it to prevent their IP's from becoming blacklisted. The downside is the cost with many charging on a per email basis and the fact that a large number of bounces (non existent emails) can result in your account being banned (although this isn't frequent as you would be informed of the bounces through their various admin tools which would allow you to remove the address from the mailing list).

As an example thee are services such as Amazon's Simple Email Service which you can use to send emails regardless of the number of emails you send and you are charged on a per email basis (i think in blocks of 1'000 or 10'000) and they have feedback channels in place so that you can interface the system with your software for the sending of emails and the automatic removal of addresses which result in hard bounces.