Email Configuration

Humio supports two options for sending emails: either SMTP on your own server, or using the Postmark application and service. How to configure Humio to use SMTP is explained in the next section. How to configure Humio to use Portmark is covered further down this page.

User Invitation

Regardless of whether you use SMTP or Postmark, assuming you enable one, an email will be sent to each new user, inviting them to use Humio.

This is enabled by default. You must set the PUBLIC_URL environment variable, though, since it’s used to generate the invitation link.

You can disable email invitations by setting the SEND_USER_INVITES environment variable to a value of false.


Humio only supports the LOGIN authentication method for SMTP or using a local SMTP server without authentication.

If you’re using Gmail, you’ll have to enable “Less Secure App Access”. Gmail defines “Less Secure” as not OAuth, which Humio does not support for SMTP. We feel that using a fixed password, rather than per-app OAuth tokens, is less secure.


This option is used to set the hostname or IP address of the server named with SERVER.


This is the port number Humio is to send SMTP messages. This is usually set to a value of 587, 465 or 25, depending on how your SMTP server is set


This is the sender email address that Humio will use when sending emails—this is the from address, not the to address. Due to DMARC policies on our domain, don’t use a sender email address.


This setting is optional. It’s for the user name to use when authenticating with the SMTP server. If not specified, communication will be attempted without authentication. If this is specified, though, you will also have to provide a value for the SMTP_PASSWORD option.


This setting is also optional, but required if giving the user name above. This variable is used to set the password to use when authenticating with the SMTP server. If not specified, communication will be attempted without authentication. If this is option specified, though, you’ll also have to provide SMTP_PASSWORD.


Use this option to enable the opportunistic TLS communication protocal. If it’s set to true, Humio will use StartTLS for the connection to the SMTP server. The default value is false, which makes it an optional setting.

It’s very common to use SMTP with Gmail and other email services. To do this, you’ll need to create an app-password that Humio can use to send emails through the email server. For Gmail, go to the Google App Password page to generate the app specific password.

Below is an example of how the SMTP section of the configuration file may look if you’re using Gmail or a similar email service:


For more information on each of these environment variables, see the Configuration reference page.

Configure Postmark

Humio can be configured to use Postmark instead of using SMTP. To do this, you’ll have to sign up for Postmark and create a new server. When you do, make sure that the email address from which Humio will be sending mail has been verified in Postmark. See their documentation on Verifying a Domain.

You’ll also have to get a security token from Postmark. When you do, add that to Humio’s configuration file with two entries like these:


You would adjust the values here for your server’s token and domain name. See the Postmark documentation page for more information on integrating Postmark with Humio.