Custom tracking pixels?

Any Marketing people here? I have a question for you:

Have any of you ever used custom tracking pixels to populate visits / email opens / events to the destination of your choice?

Tracking pixels are everywhere, but they are always supplied by some tool, and the data they are gathering is usually only available within that tool and does not integrate into any other tool in your stack. An example is Mailchimp: It does track opens and clicks within the campaigns, but that data is not accessible outside of its interface.

I'm contemplating building a custom tracking pixel provider that lets you create pixels, pass information to them via url params, and the load events get populated to a webhook / Zapier. If you think that sounds useful, I'd love to talk to you! Just comment here and I'll reach out :)