> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apollodeploy.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Open, click, and engagement tracking

> Configure project tracking behavior and a branded tracking domain

Signal can record opens, clicks, unsubscribes, read engagement, and scroll depth when the project and message settings enable the relevant behavior.
Tracking signals are useful but are not perfect measurements of human attention.

## Project settings

| Setting              | Behavior                                                           |
| -------------------- | ------------------------------------------------------------------ |
| Open tracking        | Adds a tracking image to compatible HTML email                     |
| Click tracking       | Rewrites eligible links through Signal tracking                    |
| Unsubscribe tracking | Supports project unsubscribe handling                              |
| Read engagement      | Captures supported read-engagement events when the plan enables it |
| Scroll depth         | Depends on read engagement and records supported depth signals     |

Read engagement can be plan-gated.
Scroll depth requires read engagement.

## Branded tracking domain

Use a subdomain such as `track.company.com`.
Signal shows the CNAME target that the host must resolve to.
Keep the CNAME in DNS-only mode.

<Warning>
  A project currently supports one tracking domain.
  Saving it from a domain page updates tracking for all project sends, not only that sending domain.
</Warning>

<Steps>
  <Step title="Choose the host">
    Use a dedicated tracking subdomain that does not serve your main website.
  </Step>

  <Step title="Publish the CNAME">
    Copy the exact host and target shown by Signal.
    Disable proxying or flattening that prevents the expected DNS response.
  </Step>

  <Step title="Save and verify">
    Save the tracking host, wait for DNS propagation, then run verification.
  </Step>

  <Step title="Test a controlled message">
    Check links, redirects, unsubscribe behavior, and the email timeline with an inbox you control.
  </Step>
</Steps>

## Interpret engagement carefully

Image blocking can hide opens.
Privacy proxies can create opens that do not represent a human.
Security scanners can follow links before a recipient does.
Use open and click data as directional product evidence alongside delivery, conversion, and customer behavior.