How I Built a 100ms Real-Time Cross-Device Clipboard (Next.js + Convex)

If you live entirely inside the Apple ecosystem, Universal Clipboard is basically magic. You copy text on your iPhone, and you paste it on your Mac. But the moment you step outside that walled garden—say, you have an Android phone and a MacBook, or a Windows PC and an iPad—that magic disappears. Suddenly, transferring a 12-digit 2FA code, a block of JSON, or a long URL feels like traveling back to 2005. The standard workarounds are terrible: Emailing yourself (and cluttering your inbox). Using a