Tandem - The private couples app for habits, and staying close.

My wife and I are twelve hours apart. She's in Manila. I'm in New Jersey. When I wake up, her day is ending. We had all the apps. WhatsApp, Messenger, a shared photo album nobody opened. What we didn't have was a place that was ours. Every tool we used was built for groups of friends or coworkers, and we were quietly bending it to hold a marriage. So I built Tandem for the two of us first. It lived at a private URL for months. Just me and her. Here's what I learned: long distance isn't a communication problem. We talked constantly and still didn't feel like we shared a life. It's a presence problem. The fix wasn't more messages. It was a clock that shows what she's doing right now. Habits we check off separately but see together. A heart button that does nothing except say "you crossed my mind." A room where we can watch the same thing at the same time and sing badly at each other. And letters that take a few hours to arrive. On purpose. That last one changed how I build. Every instinct in software says make it faster. But the letters work because they're slow. The waiting is the point. That was when I realized I wasn't designing an app. I was designing a relationship. Now it's open to any couple. Still, at heart, a private thing I share with my wife. Everyone else is just welcome in.