Let's say you run a portfolio of five Shopify apps or nine Trello power-ups. You'd love to leverage email marketing for your SaaS business, but your brain is on fire. Five separate email lists is obviously overkill.

What's the best way to organize your email marketing? How do you cross-sell between multiple SaaS products, run multiple onboarding campaigns, and not upset, confuse, or lose your customers?

This guide will show you the way.