Configure StartOS with third-party SMTP credentials so that services like NextCloud, Vaultwarden, and Gitea can send email notifications. SMTP is configured under System > SMTP.
Warning
This guide is not for using StartOS as an email server. It is for granting StartOS the simple ability to send emails through a 3rd party SMTP server.
We recommend Forward Email: it is open source and privacy-focused, and sends from your own domain. StartOS has presets for Amazon SES, Forward Email, Gmail, Mailgun, Proton Mail, and SendGrid, covered below. To use any other provider, choose Other and enter its settings.
To use Amazon SES you will need:
An Amazon Web Services (AWS) account. If you don’t have one, you can register here for free.
A verified identity to send from: either your own domain name (add the DNS records Amazon gives you) or a single email address, under Identities in the SES console.
New SES accounts start in the sandbox, which can only send to addresses you have also verified. To send to anyone else, request production access from the SES Account dashboard.
Open the SES console and check the region selected in the top bar. Credentials, verified identities, and the SMTP host are all specific to this region, so use the same one throughout.
Choose SMTP settings in the left navigation pane. The page shows two cards: Mail Manager SMTP (marked “Recommended”) and IAM SMTP credentials.
In the IAM SMTP credentials card, click Create IAM credentials. The IAM console opens. Do not use the Mail Manager card’s Create SMTP credentials button: it creates an ingress endpoint, a separately billed product that is not needed.
Enter a user name (or keep the default) and click Create user.
Click Show under SMTP password, then Download .csv file. The SMTP user name and password are shown only once; save them somewhere secure, such as your Vaultwarden password manager. The user name is an access key ID (starts with AKIA); the password is not your AWS secret access key.
In StartOS, go to System > SMTP, select Amazon SES as the provider, and enter the values below. Choosing Amazon SES pre-fills the host for us-east-1 and defaults to TLS on port 465.
Parameter
Value
Host
email-smtp.<region>.amazonaws.com, e.g. email-smtp.us-east-1.amazonaws.com
Connection Security
TLS
Port
465
From Address
an address at your verified domain, or your verified email address
Username
your SMTP user name (from above)
Password
your SMTP password (from above)
Note
Replace <region> in the Host with the region you created the credentials in, e.g. email-smtp.eu-west-1.amazonaws.com. The SMTP settings page in the SES console shows the exact hostname for that region. To use STARTTLS instead, set Connection Security to STARTTLS and the Port becomes 587. The From Address may optionally include a display name, e.g. Your Name <you@yourdomain.com>.
To use Forward Email you will need a domain name on a Forward Email paid plan, which includes outbound SMTP.
Follow Forward Email’s Send Email with Custom Domain guide until it has you configure an email application. By then your domain is set up for outbound SMTP and you have an alias to send from, such as no-reply@yourdomain.com, and its generated password.
In StartOS, go to System > SMTP, select Forward Email as the provider, and enter the values below. Choosing Forward Email pre-fills the host and defaults to TLS on port 465.
Parameter
Value
Host
smtp.forwardemail.net
Connection Security
TLS
Port
465
From Address
no-reply@yourdomain.com
Username
no-reply@yourdomain.com
Password
the alias’s password (from above)
Note
The From Address must be the alias in Username; Forward Email rejects mail sent from any other address. It may optionally include a display name, e.g. Your Name <no-reply@yourdomain.com>.
Access your Google 2-step verification settings: https://myaccount.google.com/signinoptions/two-step-verification.
Enable 2-Step verification if not already.
Go to the App Passwords page: https://myaccount.google.com/apppasswords. Google no longer links to it from the 2-Step Verification page, so navigate there directly.
Choose a name for the new App Password. You may call it anything, such as “SMTP”, then click “Create”.
A random 16-character password will be created and shown to you. This is your app password. Save it somewhere secure, such as your Vaultwarden password manager, then click “Done”.
In StartOS, go to System > SMTP, select Gmail as the provider, and enter the values below. Choosing Gmail pre-fills the host and defaults to TLS on port 465.
Parameter
Value
Host
smtp.gmail.com
Connection Security
TLS
Port
465
From Address
your-username@gmail.com
Username
your-username@gmail.com
Password
your App Password (from above)
Note
Selecting Gmail pre-fills and locks the Host, and choosing TLS locks the Port at 465. To use STARTTLS instead, set Connection Security to STARTTLS and the Port becomes 587. The From Address may optionally include a display name, e.g. Your Name <your-username@gmail.com>.
To use Mailgun you will need a Mailgun account with a sending domain you have verified by adding the DNS records Mailgun gives you.
In Mailgun, open your domain’s SMTP credentials and create a credential, such as no-reply@mg.yourdomain.com. Save its password somewhere secure; Mailgun shows it only once. See Mailgun’s SMTP credentials guide.
In StartOS, go to System > SMTP, select Mailgun as the provider, and enter the values below. Choosing Mailgun pre-fills and locks the host and defaults to TLS on port 465.
Parameter
Value
Host
smtp.mailgun.org
Connection Security
TLS
Port
465
From Address
an address at your sending domain
Username
your SMTP credential’s login
Password
your SMTP credential’s password
Note
A domain in Mailgun’s EU region sends through smtp.eu.mailgun.org. Choose Other as the provider to enter that host.
Access to Proton Mail’s SMTP settings is currently only made available by Proton to their customers with Proton for Business, as well as certain higher tier individual and family plans (Proton Duo, Proton Family – both with “SMTP Submission” as a listed feature), and then only when you point a custom domain to your account.
To set up Proton Mail for SMTP you will need:
To purchase and point a domain name from a domain registrar to Proton’s servers by following this guide here: Custom Domain
To follow the steps in the section How to set up SMTP in the guide here: SMTP Submission
To use SendGrid you will need a SendGrid account with a verified sender: either a single sender address or an authenticated domain.
In SendGrid, create an API key with Mail Send permission. Save it somewhere secure; SendGrid shows it only once. See SendGrid’s SMTP integration guide.
In StartOS, go to System > SMTP, select SendGrid as the provider, and enter the values below. Choosing SendGrid pre-fills and locks the host and defaults to TLS on port 465.