Resumability, WTF?

Resumability is a framework technique that avoids the performance overhead of traditional hydration by serializing full application state on the server and attaching global event handlers, so the browser can resume execution without re-running the entire component tree. The post explains why hydration exists (modern declarative frameworks need to re-run code to restore interactive state), its downsides (blocking main thread, input lag, uncanny valley), and how resumability solves this by treating the app like a hibernating computer. It also covers the complementary techniques of Progressive Hydration and Partial Hydration (Islands architecture), and the serialization challenges involved. Frameworks like Qwik and Marko 6 are cited as real-world implementations.