Error Boundaries in Next.js App Router — Handling Failures Gracefully (opens in new tab)

Most Next.js applications handle the happy path well. A request comes in, data loads, components render, user sees the page. Error handling is where applications often reveal their real quality — and where App Router introduces some nuances worth understanding. Here's how error boundaries work in App Router, what the error.js file actually does, and the patterns that make failure handling feel intentional rather than afterthought. This is the approach I use in production for a free AI image g...