What engagement metrics measure
Engagement metrics report how recipients interact with your mail. They cover two tracked actions:
open: the number of times the email was opened.click: the number of clicks on tracked links in HTML messages.
Each event count is paired with the number of recipients who could have performed the action, so you can compute open and click rates:
open_tracking_delivered: the number of recipients of delivered HTML messages where open tracking was enabled in the
send request.click_tracking_delivered: the number of recipients of delivered HTML messages containing tracked links, where click
tracking was enabled in the send request.
Messages sent without the corresponding tracking enabled do not contribute to either count.
Use these metrics to measure campaign reach, identify content that resonates, and compare engagement across
send times or audience segments.
Example query
The example below requests daily engagement totals for a single campaign in January 2026.
#!/usr/bin/env bash
# Retrieve daily open and click counts for a single campaign.
set -u
: "${MAILCHANNELS_API_KEY:?Set MAILCHANNELS_API_KEY before running}"
curl -G "https://api.mailchannels.net/tx/v1/metrics/engagement" \
-H "X-Api-Key: $MAILCHANNELS_API_KEY" \
--data-urlencode "start_time=2026-01-01T00:00:00Z" \
--data-urlencode "end_time=2026-01-31T23:59:59Z" \
--data-urlencode "campaign_id=newsletter_jan_2026" \
--data-urlencode "interval=day"
Open and click tracking is not available in our free tier.
