Ask HN: How do you measure your funnel?

We are working on a tool to help people measure their conversion funnels. For example:

Unique visitors to website -> User Signups -> Paid Customers

This would be high-level funnel tracking a whole site. But you could also track individual pages and different conversion types (email subscriptions or webinar signups).

We have built a simple tool to do this automatically using Google Analtyics for unique visitors, Intercom for signups and Stripe for paid customers.

But I am curious what tools you use to track things like this??