Reliably send e-mail via Amazon Web Services' Simple E-mail Service: amazonses



Reliably sending e-mail from a device or cloud server you control, unfortunately, is not easy. Because historically, e-mail has had no concept of security, and spammers are sending trillions of unwanted and malicious messages, most e-mail providers have implemented strict, and always-changing heuristics that determine whether or not an e-mail they received ever gets forwarded to the recipient’s e-mail in-box. In our experience, naively sending off e-mail via SMTP from a random cloud server results in about 50% delivered messages, with the rest being discarded or lost on the way.

However, many Apps on UBOS need to reliably send e-mail, such as to confirm account sign-ups.

Enter App amazonses. If you use ubos-admin createsite to setup a Site called which will run, say, Mediawiki, enter mediawiki as the name of the App to run at this Site, but then continue and specify amazonses as the second App running on the same Site.

ubos-admin createsite will ask you for credentials (more about those below), but once you have entered them, UBOS will send all outgoing e-mail originating from via Amazon Web Services’ Simple E-mail Service (SES). Amazon, not surprisingly, works hard to be on the good side of e-mail providers world-wide, which means that the e-mail you send via them has a high reputation, and will likely be delivered (unless you send spam, of course).

If you run more than one Site on the same Device, outgoing e-mail originating from a domain other that at the one to which you deployed amazonses will not be affected and will continue to be sent directly, without going through Amazon SES. If you would like that outgoing e-mail to go through SES as well, simply add amazonses as an additional App to that Site as well.

Note that you need to have a control of the DNS settings of the domain from which you want to send your e-mails, otherwise Amazon will not permit you to do so.

How to run amazonses as a second App if ubos-admin createsite does not ask

Some Apps, such as Mastodon, can only run at the root of a Site. When you create a new Site with such an App, ubos-admin createsite will not ask for a second App, because other web Apps cannot run at the same Site. However, amazonses is not a web App (it has no web interface), so it can run! So how can you enter it?

Simple: always specify amazonses as the first App when running ubos-admin createsite. And then enter mastodon, or whatever other App you want to run at the root of the Site as the second App.

How to sign up for Amazon Web Services’ Simple E-mail Service and get credentials

Here are the steps:

  1. Go to and log into your Amazon Web Services account. If you do not have an Amazon Web Services account, create one.

  2. In the left sidebar, select “Domains”

  3. Click on “Verify a New Domain” and enter the name of your DNS domain from where your e-mail will originate, such as

  4. At your domain name registrar, or DNS provider, enter the additional domain name records that Amazon displays. You can ignore all aspects of “receiving e-mail” as UBOS currently is not set up to receive and/or dispatch incoming e-mails.

  5. Wait until you have received e-mail confirmation that your domain has been verified, and the status of your domain in the SES console has turned “verified”.

  6. Select “SMTP settings” in the left sidebar in the SES console.

  7. Click “Create my SMTP credentials”.

  8. Click through the wizard, and select “Show User SMTP Security Credentials”. This shows two values. Enter those two values when ubos-admin createsite asks for those values (see discussion above). “SMTP Username” is the same thing as aws_access_key_id and “SMTP Password” is the same as aws_secret_key.


It is possible that Amazon first places your account into a “sandbox”, which strongly limits which e-mail addresses you can send messages to. Usually, requesting to be let out of the sandbox is a straightforward process. Check the SES control panel whether you need to do that.