gotosocial/docs/configuration/smtp.md
agx bf46b87343 [docs] Document STARTTLS behavior (#4301)
The docs currently state that sending via `localhost` unencrypted can work but that's only true when the SMTP server doesn't offer `STARTTLS`. Make that a bit more obvious.

Couldn't test the doc build as miniconda isn't in my distro and pip wouldn't find all dependencies.

# Description

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [ ] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [ ] I/we have commented the added code, particularly in hard-to-understand areas.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [ ] I/we have run tests and they pass locally with the changes.
- [ ] I/we have run `go fmt ./...` and `golangci-lint run`.

Co-authored-by: Guido Günther <agx@sigxcpu.org>
Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4301
Co-authored-by: agx <agx@noreply.codeberg.org>
Co-committed-by: agx <agx@noreply.codeberg.org>
2025-07-03 16:52:07 +02:00

4.8 KiB

Email Config (smtp)

GoToSocial supports sending emails to users via the Simple Mail Transfer Protocol or smtp.

Configuring GoToSocial to send emails is not required in order to have a properly running instance. Still, it's very useful for doing things like sending confirmation emails and notifications, and handling password reset requests.

In order to make GoToSocial email sending work, you need an smtp-compatible mail service running somewhere, either as a server on the same machine that GoToSocial is running on, or via an external service like Mailgun. It may also be possible to use a free personal email address for sending emails, if your email provider supports smtp (check with them--most do), but you might run into trouble sending lots of emails.

To validate your configuration, you can use the "Administration -> Actions -> Email" section of the settings panel to send a test email.

!!! warning Pending an smtp library update, currently only email providers that work with STARTTLS will work with GoToSocial. STARTTLS is generally available over port 587.

For more info, see:

- [STARTTLS vs SSL vs TLS](https://mailtrap.io/blog/starttls-ssl-tls/)
- [Understanding Ports](https://www.mailgun.com/blog/email/which-smtp-port-understanding-ports-25-465-587/)
- [Port 587](https://www.mailgun.com/blog/deliverability/smtp-port-587/)

!!! info For safety reasons, the smtp library used by GoToSocial will refuse to send authentication credentials over an unencrypted connection, unless the mail provider is running on localhost.

!!! info If your SMTP server offers STARTTLS in its EHLO response GoToSocial will try to use it. The SMTP server must hence also have valid SSL certificates. If you're sending mail via localhost and don't want to set up certificates make sure that your SMTP server doesn't announce STARTTLS support. In postfix this can be done via -o smtpd_tls_security_level=none.

Settings

The configuration options for smtp are as follows:

#######################
##### SMTP CONFIG #####
#######################

# Config for sending emails via an smtp server. See https://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol

# String. The hostname of the smtp server you want to use.
# If this is not set, smtp will not be used to send emails, and you can ignore the other settings.
# Examples: ["mail.example.org", "localhost"]
# Default: ""
smtp-host: ""

# Int. Port to use to connect to the smtp server.
# In the majority of cases, you should use port 587.
# Examples: []
# Default: 0
smtp-port: 0

# String. Username to use when authenticating with the smtp server.
# This should have been provided to you by your smtp host.
# This is often, but not always, an email address.
# Examples: ["maillord@example.org"]
# Default: ""
smtp-username: ""

# String. Password to use when authenticating with the smtp server.
# This should have been provided to you by your smtp host.
# Examples: ["1234", "password"]
# Default: ""
smtp-password: ""

# String. 'From' address for sent emails.
# Examples: ["mail@example.org"]
# Default: ""
smtp-from: ""

# Bool. If true, when an email is sent that has multiple recipients, each recipient
# will be included in the To field, so that each recipient can see who else got the
# email, and they can 'reply all' to the other recipients if they want to.
#
# If false, email will be sent to Undisclosed Recipients, and each recipient will not
# be able to see who else received the email.
#
# It might be useful to change this setting to 'true' if you want to be able to discuss
# new moderation reports with other admins by 'replying-all' to the notification email.
# Default: false
smtp-disclose-recipients: false

Note that if you don't set Host, then email sending via smtp will be disabled, and the other settings will be ignored. GoToSocial will still log (at trace level) emails that would have been sent if smtp was enabled.

When are emails sent?

Currently, emails are sent:

  • To the provided email address of a new user to request email confirmation when a new account is created via the sign up page or API.
  • To instance admins when a new account is created in this way.
  • To all active instance moderators + admins when a new moderation report is received. By default, recipients are Bcc'd, but you can change this behavior with the setting smtp-disclose-recipients.
  • To the creator of a report (on this instance) when the report is closed by a moderator.

HTML versus Plaintext

Emails are sent in plaintext by default. At this point, there is no option to send emails in html, but this is something that might be added later if there's enough demand for it.

Customization

If you like, you can customize the templates that are used for generating emails. Follow the examples in web/templates.