What is passive income? It’s a way to earn steady money with little to no daily effort. Note that we didn’t say no effort at all. Earning passive income is not a sit-on-your-butt-and-make-fast-money gig. You’ll need to put in the work—at least on the front end. Some passive income ideas—like building a blog or an app—take time (and sometimes money) to get up and running. But if you play your cards right, they could eventually earn you money while you sleep.