I'm building a multi-tenant CMS application that will be hosted on Heroku (which uses Amazon EC2, etc). I will also be adding the ability to register/transfer a domain through the application. I would like to add the ability for my customers to be able to have email hosting included and import/manage email addresses through the application.

I have been looking into open source mail servers (such as Postfix) and the feasibility of hosting email. I don't think Amazon EC2 allows hosting your own email server, so I guess I will also be looking for a place to host this email server. What sort of advice can you give me on the topic of hosting an email server for multiple customers/domains?

  • Asking for software/product recommendations is off-topic on all Stack Exchange sites.
    – Chris S
    Jan 3, 2013 at 4:37

4 Answers 4


EC2 has no restrictions on running mailservers.

If you haven't previously run a mailserver, you're likely to be in over your head attempting to run any of the common *nix mailservers (sendmail, postfix, qmail, courier) - there's a fairly steep learning curve, none could be characterized as plug-and-play. You'd do better to outsource the email hosting.

  • Do you have any recommendations on companies I can outsource the email hosting to?
    – Andrew
    Oct 10, 2011 at 3:30
  • You can dicuss this Q with me Oct 10, 2011 at 9:05
  • A year later and I'm still thinking about this question. I would be happy to outsource the email hosting to something like Google Apps, but now that Google Apps does not have a free version, I'm looking for an affordable solution (preferably free) to keep my costs down. I'm willing to do the work of running my own mail server as long as I know I'm following industry best-practices. Also, I'm interested in having the flexibility of being able to manage email addresses through some sort of web app (or API) that I build myself.
    – Andrew
    Dec 28, 2012 at 7:53
  • You might take a look at Zimbra, it's essentially an entire email hosting suite. www.zimbra.com. The main product is payware, but it's open source, so you can download the suite for free - as long as you're willing to forgoe formal support for the product. note: i've never used it myself, but have heard good things about it. there are other options - the vpopmail project is one i used for many years, when i ran an email hosting business. it's based on qmail, and vpopmail hasn't had much development for a while. it does work thoug. current owner hosts email for many hundreds of domains.
    – anastrophe
    Dec 28, 2012 at 21:53
  • @Andrew A year is plenty of time to learn to use Postfix :) Jan 3, 2013 at 3:30

While EC2 has no restriction on running a mailserver they do have a restriction on how much email you can send by default.

You can apply for higher limits as well as have your Elastic IP reverse DNS records set by Amazon by filling in a form (only accessible if you login with your AWS account).

However I do agree with anastrophe running a mailserver isn't something to be taken lightly.

  • Ah yes, I'd forgotten about filling out those few forms to allow for higher volume, reverse DNS, etc.. We send about 160K messages out each night from each of our four EC2 MTA's. Performance isn't awesome, but it's adequate for keeping some IP's alive in reputation scoring, in case our main MTA's are out of commission for some reason.
    – anastrophe
    Oct 9, 2011 at 19:14

When you talk about keeping your costs down make sure you are considering the cost to yourself or your staff of maintaining an email server. As previously mentioned there is a very steep learning curve including getting the initial setup right and over the first year or two of running the server dealing with spam, user requests, handling outages, redundancy etc etc. Compared to hosting a webserver, a mail server is much more demanding on your time. As a very small service provider, I regret setting up an email server - it has been the biggest pain, and not rewarded me in line with the effort put in.

Consider the options of outsourcing the email and passing on the cost to your customers (by which I mean whoever is paying you - which might be advertisers rather than end users).

Or set up your system so that your users can use an existing mail account of their choice. Do any of your customers not already have an email address/service? Do any of your customers really need another one?

Of course, maybe you really want to add the mail admin string to your bow, in which case go for it! If you opt for Postfix as your MTA, then The Book of Postfix is a worthwhile investment, and there is a pretty good website out there for asking questions when you encounter problems or don't understand something... Can't quite recall what it is right now :-)


I've hosted my own email server using Postfix for years and I recently looked at options for outsourcing. Most affordable services I looked at only offered email hosting as part of a domain and web hosting package. However, RunBox offers standalone email hosting for a good price and are worth checking out. They offer a free trial period so you can test it out and see if it's a good fit for you.

  • Have you used RunBox?
    – Andrew
    Jan 4, 2013 at 23:28
  • @Andrew I am in a trial period wirh Runbox now. I already had the domain registered, so them once the account was created, I just pointed my MX record at their server and it was working. Webmail and IMAP working, no problem, and adding mailboxes and aliases was straightforward. Jan 5, 2013 at 8:01

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