react-errors-hydration

Hydration mismatches in React SSR happen when server-rendered HTML differs from client render output, typically caused by using browser-only APIs, Date objects, or Math.random during initial render.

Fix hydration mismatch warnings by applying deterministic server rendering patterns like the isClient state, useEffect for client-only updates, or suppressHydrationWarning to safely handle environment-dependent content differences.

Yes, React 19 enhances hydration mismatch handling with partial recovery capabilities and the onRecoverableError callback, allowing you to capture and instrument mismatch events in production environments.

Use suppressHydrationWarning in React when you intentionally render different content on the server versus the client, such as timestamps or browser-specific APIs, and need to suppress the mismatch warning without breaking hydration.

Detect hydration mismatch causes by identifying non-deterministic render content like Date, Math.random, or browser API usage, then applying diagnostic patterns to isolate which component produces differing server and client HTML.

Yes, render client-only components safely in React SSG by using the isClient pattern or useEffect to defer browser-specific rendering until after hydration, ensuring server and client output matches initially.