What Is Partial Hydration?
Partial hydration is the technique of hydrating only the components that need interactivity rather than the entire page tree. Static sections remain as the HTML the server produced, with no attached client logic. This narrows the amount of JavaScript that must download and execute to make the page work.
Why it matters
Hydrating selectively reduces main-thread work and improves time to interactive on content-heavy pages. It is the underlying idea behind island architectures.
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