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

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.

Set Base64 Data (Create data pix) Creates a variable data containing a Base64-encoded transparent PNG image (1x1 pixel).

Convert to Binary (Create img bin) Converts the Base64 data string into a binary file. Sets MIME type to image/png.

Respond to Webhook (Respond to Webhook) Sends the binary image file in the HTTP response.

Logging (Do anything to log) Placeholder node to log or process the id or request metadata. You can access the id using {{$json"query"}}. You can also use any parameter you want

✉️ How to Use in Emails

Embed the image in an HTML email like this:

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).