Transparent tracking pixel for email open detection

📌 Description

This workflow serves a 1x1 transparent PNG image via a webhook, which can be embedded in an email to track when the email is opened. When the image is loaded by the recipient's email client, the webhook is triggered, optionally capturing a userId to identify who opened the email.

📂 Workflow Steps

1. Webhook Trigger (Request img)

   • Path: /webhook/change-with-your-id
   • Triggered by an HTTP request (e.g. when the image is loaded in an email).
   • Accepts a query parameter id to identify the recipient.

2. Set Base64 Data (Create data pix)

   • Creates a variable data containing a Base64-encoded transparent PNG image (1x1 pixel).

3. Convert to Binary (Create img bin)

   • Converts the Base64 data string into a binary file.
   • Sets MIME type to image/png.

4. Respond to Webhook (Respond to Webhook)

   • Sends the binary image file in the HTTP response.

5. Logging (Do anything to log)

   • Placeholder node to log or process the id or request metadata.
   • You can access the id using {{$json["query"]["id"]}}.
   • You can also use any parameter you want

✉️ How to Use in Emails

Embed the image in an HTML email like this:

<img src="https://&lt;your-n8n-instance&gt;/webhook/db4880e7-2134-4994-94e5-a4a3aa120440?id=1234" width="1" height="1" alt />

When the email is opened and the image is loaded, the workflow will be triggered.

🛠️ Notes

• Some email clients block images by default; this may prevent tracking.
• You can enhance the workflow to store open events in a database, log the timestamp, IP, or user agent.
• Make sure to comply with data privacy and consent regulations (e.g. GDPR).