Open and click tracking

Open and click tracking is an automatic feature available in campaigns (bulk). When you send a campaign with HTML content, MailerDash injects a tracking pixel and rewrites links to capture recipient interactions.

Tracking does not apply to transactional sends (POST /v1/mail/send).

How it works

Open tracking (pixel)

At send time, MailerDash inserts an invisible 1×1px pixel at the end of the HTML <body> (or at the end of the content if there is no <body>):

<img src="https://track.mailerdash.com/o/<token>" width="1" height="1"
     alt="" style="display:none;border:0;width:1px;height:1px;">

When the email client loads the image, an open is recorded and associated with that send and contact.

Click tracking (link rewriting)

All <a href="..."> elements in the HTML that point to http:// or https:// URLs are rewritten to pass through the tracking domain:

<!-- Before -->
<a href="https://mi-app.com/promo">Ver oferta</a>

<!-- After sending -->
<a href="https://track.mailerdash.com/c/<token>">Ver oferta</a>

The redirect captures the click and sends the recipient to the original URL in under a second.

Links that are not rewritten:

mailto:, tel:, javascript:, anchors (#sección)
Unresolved placeholders ({{variable}})
The List-Unsubscribe and One-Click unsubscribe link
URLs that already point to the tracking domain

Where to view analytics

Campaign analytics

GET /v1/bulk/campaigns/{id}/analytics
Authorization: Bearer $MAILERDASH_API_KEY

Response (summary):

{
  "campaign_id": "camp_abc123",
  "delivered": 1250,
  "opens_unique": 342,
  "opens_total": 489,
  "clicks_unique": 118,
  "clicks_total": 201,
  "bounces": 12,
  "complaints": 2,
  "unsubs": 5,
  "rates": {
    "open": 0.2736,
    "ctr": 0.0944,
    "ctor": 0.3450,
    "bounce": 0.0096,
    "complaint": 0.0016,
    "unsub": 0.0040
  },
  "top_links": [...],
  "timeline": [...],
  "detail_window_days": 90
}

Also append ?format=csv to export per-recipient detail with columns email, status, sent_at, first_opened_at, first_clicked_at.

Aggregated rates across campaigns

GET /v1/bulk/analytics/rates?period=7d

period accepts 24h, 7d, or 30d. Returns consolidated metrics for all campaigns on your key within that window.

Contact engagement

GET /v1/bulk/contacts/{email}/engagement

Returns the interaction history (opens, clicks, bounces, complaints, unsubscribes) for a specific contact, useful for segmentation and deliverability diagnostics.

Unique vs. total

Metric	Meaning
`opens_unique`	Number of distinct contacts who opened at least once
`opens_total`	Total opens (includes multiple opens from the same contact)
`clicks_unique`	Distinct contacts who clicked at least one link
`clicks_total`	Total clicks (includes repeated clicks and clicks on multiple links)

For calculating open rates, always use opens_unique / delivered; opens_total is useful for measuring deep engagement (if a contact opens the email multiple times).

Data retention

The detail_window_days: 90 field indicates that individual open/click events (detailed per-recipient timeline) are kept for 90 days. Aggregated campaign counters are retained indefinitely.

See the full bulk endpoint reference at /reference/bulk/.