Hey ​@Adam Davis, Emily here from Support Engineering at Intercom

You can trigger an email message in Intercom via the API by making a GET request to the Intercom Conversations API with the appropriate user parameters. This allows you to trigger message matching for a user after sending data updates or event calls, which could include passing unique, one-time use invite links as part of your user data or event payload.

We don’t explicily support sending one time codes - but it could indeed be made possible using this custom solution on your side