Caution
You are not reading the latest stable version of this documentation. If you want up-to-date information, please have a look at 0.3.5.x.
There are several services that are able to take advantage of a Simple Mail Transfer Protocol (SMTP) server in order to send emails. The most common third party SMTP services are GMail and Amazon SES. Some example services that you may wish to use this functionality with are BTCPay Server, Ghost, Gitea, Nextcloud, Synapse, and Vaultwarden.
In order to get SMTP credentials for use in a StartOS service, you can follow one of these third party guides: