Opens and clicks

Open and click tracking is on for every email you send through the API and SMTP. There is no setting to turn it off for a message or a site.

How opens are tracked#

We add a 1×1 transparent image to the end of the HTML part. Its address is https://securessmtp.com/e/o/<token>, where the token identifies the email. When a mail app loads the image, we record an open. Emails you send as plain text only also get an HTML part, so they are tracked too.

How clicks are tracked#

Every http and https link in an <a href="..."> tag in the HTML part is rewritten to https://securessmtp.com/e/c/<token>?u=<encoded link>. When someone clicks, we record the click and redirect them to the original address. We do not rewrite:

• links whose address contains unsubscribe;
• mailto: and tel: links, and links to anchors on the page;
• links in the plain-text part.

A click also counts as an open if no open was recorded for that email yet.

How accurate the numbers are#

• Mail apps that block images by default record no open until the reader allows images.
• Some providers load images on their own servers, for example Apple Mail Privacy Protection and the Gmail image proxy. That can record an open the person never made, or hide repeat opens.
• Security scanners at some companies follow links in incoming mail, which can record clicks.

Use opens and clicks to compare emails with each other, not as exact counts.

Where to see them#

• Email analytics (/app/forms/email-analytics): how many emails were opened and clicked, as a share of delivered emails, for the last 7, 30 or 90 days. It also breaks the numbers out per sending domain and per recipient.
• Webhooks: email.opened and email.clicked are posted on every open and every click, not only the first. Each has message_id, to and subject; the clicked link is not included. See Webhooks.