Good to know: Event source

The Source is an event source. This means that it sends data as events, which are behaviors or occurrences tied to a user and a point in time. Data from these sources can be loaded into your Segment warehouses, and also sent to Segment streaming destinations. Learn more about cloud sources. is an automated email tool. It lets you set up rules to automatically send emails to your users after they perform actions, making drip email campaigns really easy.

Take your company’s email analysis to the next level by adding as a Source to Segment. Segment automatically collects email events like Email Delivered and Email Opened, forward them to your destinations, and load them into your data warehouse. 

In your favorite BI or analytics tool, you’ll be able to analyze your email campaigns in SQL or through drag-and-drop reports. And, you’ll be able to join your data with the event data you’re already sending through Segment to analyze the down-funnel effects of your emails. Learn more about how you can use with Segment.

Good to know: This page is about the Segment source, which sends data into Segment. There’s also a page about the Segment destination, which receives data from Segment!

Getting Started

If you have previously enabled sending email events using the destination during our beta (using a project write key), you do not need to create new source. Your email data will continue to flow as normal.

  1. From your workspace’s<your-workspace>/sources page, click Add source.

  2. Choose

  3. Give the Source a nickname and a schema name. The nickname is a label used in the Segment interface, and the schema name is the namespace you query against in your warehouse. We recommend using a name that reflects the Source itself, like Customerio for nickname and customerio for the schema name.

  4. The next page (“Overview”) displays your Segment write key for Copy this write key. 

  5. To finish the set up, go to your account, go to Settings > Integrations > Segment, and enter the Segment write key.

  1. Click Save.

  2. In Segment, click into your Source in From there you’ll be able to add Destinations where you want to see email events.

That’s it! As you send emails, events will now be sent to your destinations and automatically loaded into any warehouses you have enabled. 


Stream uses our stream Source component to send Segment email events. It uses a server-side track method to send data to Segment. These events are then available in any destination that accepts server-side events, and available in a schema in your data warehouse, so you can query using SQL. 

The default behavior is for to pass the userId associated with the email recipient as the userId. There are cases in which does not have an associated userId, in which case the email address will be passed in as the anonymousId


Collections are the groupings of data we pull from your Source. In your warehouse, each collection gets its own table, as well as a tracks table that aggregates all the events into a single table. 

Collection Type Description
Email Delivered Event Message has been successfully delivered to the receiving server
Email Opened Event Recipient has opened the HTML message. You need to enable Open Tracking for getting this type of event
Email Link Clicked Event Recipient clicked on a link within the message. You need to enable Click Tracking for getting this type of event
Email Unsubscribed Event Recipient clicked on message’s subscription management link
Email Bounced Event Receiving server could not or would not accept message
Email Marked as Spam Event Recipient marked message as spam

Send data to

The Source works better when you also connect as a destination. With the Destination, you can use Segment to send user and event data from which you trigger email campaigns. Want to start sending website or mobile data TO Head on over to our destination docs.

This page was last modified: 20 Oct 2020

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