SMTP Integration

This integration is used by Clerk Invoices and Clerk Quotes apps.

SMTP integration allows emailing invoices and quotes from your own SMTP server that sends emails from your custom domain. We support both SSL and STARTTLS encryption.

You need to set the following parameters to enable the integration. Usually, you can find them at your email service provider help center or ask your system administrator:

• SMTP server address
• SMTP server port
• User and password to log in to the SMTP server
• From name and from email that are used to send emails to your clients

Currently, we don’t test these parameters when you save them in the app, so try sending any invoice or quote for testing them.

Please note, that some email service providers require tweaking some settings or using app passwords to send emails via pure SMTP protocol.

You can find some instructions to connect to popular email service providers below. They work at this moment, but they can always be changed by your service provider in the future, so please always look at the email service provider help center for more details.

Connecting to the Gmail and Google Workspace SMTP Server

Gmail and Google Workspace require you to use app passwords for SMTP authentication, your regular password will not work. And using app passwords also requires enabling 2-step verification. You can find more instructions in the Sign in with app passwords Google article.

You need to set the following parameters in the Clerk Invoices or Clerk Quotes apps for connecting to the Gmail or Google Workspace SMTP server:

Connecting to the Microsoft Exchange Online SMTP Server

Microsoft Exchange Online requires many things to be set up before you can use its plain SMTP server. You need to:

• Enable the Authenticated SMTP option for the user that will be used to send invoices or quotes
• If you want to use a standard user password to connect to SMTP, you need to disable multi-factor authentication for that user. Or you can use app passwords if you want to keep the multi-factor auth.
• Make updates to your security settings as described in this article (items 3 and 4):
  • Disable security defaults, since they always block SMTP protocol authentication. If you still need the high-security level, you can switch to a more flexible Conditional Access policies that allow tweaking all security settings.
  • Exclude the user from a Conditional Access policy that blocks Legacy Authentication

We also recommend using app passwords instead of regular user passwords for higher security. Here are some tips on how you can enable and create app passwords for your Microsoft 365 user account:

• Enable Allow users to create app passwords option in the Microsoft Entra ID portal
• Make sure that the multi-factor auth status is Enforced for the user that will create app passwords
• Now you can create app passwords from the Security info page
• In our case, we had to wait up to 24 hours before the new app password started working

You need to set the following parameters in the Clerk Invoices or Clerk Quotes apps for connecting to the Microsoft Exchange Online SMTP server: