Understanding Hydration Mismatches and Layout Shifts

What Are the Symptoms?

  • Content appears correct initially but shifts after hydration
  • Next.js console shows hydration mismatch or re-render warnings
  • Custom themes render incorrectly or flash default styles briefly
  • Text content, spacing, or dimensions differ across renders

Why It Matters

Hydration mismatches not only create visual bugs but also degrade SEO and accessibility. For apps using SSR (like with Next.js), they can significantly hurt performance scores and introduce inconsistent UX across devices.

Root Causes

1. Non-Deterministic Style Generation

Chakra UI generates styles at runtime. When ChakraProvider and custom themes are not properly initialized during SSR, mismatches occur between initial HTML and the hydrated client render.

2. Incorrect Color Mode Initialization

Chakra uses a ColorModeScript to sync light/dark mode across SSR and client. Omitting or misplacing this script causes theme flickers or default style fallbacks.

3. Dynamic Layout Logic Inside Render

Using window-based calculations (like window.innerWidth) or rendering conditionally on client-only values causes divergence between server and client renders.

4. Unstable Component Keys or Conditional Mounting

Improper use of keys or layout-specific components rendered conditionally without consistent fallback leads to unpredictable UI diffs on hydration.

Architecture: Chakra UI and SSR

How Chakra UI Renders on Server

Chakra UI relies on emotion-style caching. During SSR, style sheets are extracted and injected into the HTML output. If the theme or style cache is missing or inconsistent, layout shifts and invalid markup occur post-hydration.

Integration with Next.js

Next.js requires custom Document and App wrappers to properly support Chakra's SSR workflow. Both emotion's cache provider and Chakra's theme context must be included on the server and client consistently.

Diagnostics and Debugging

1. Enable Strict Mode and React DevTools

StrictMode exposes layout instability by double-invoking renders. Use DevTools to inspect if Chakra styles are applied before hydration completes.

2. Check for Missing ColorModeScript

Ensure your _document.tsx or _document.js includes <ColorModeScript /> inside the <body> tag to avoid theme flickers.

3. Inspect Hydration Warnings

Console messages like Text content did not match often indicate that SSR and CSR outputs differ. Use React DevTools profiler to trace culprit components.

4. Compare SSR HTML Output

Use View Source and browser inspector to compare initial SSR output with post-hydration DOM. Look for spacing, font size, or color discrepancies.

Step-by-Step Fix Strategy

1. Add Emotion Cache Provider

// pages/_document.tsx
import createEmotionCache from '../lib/createEmotionCache';
import { CacheProvider } from '@emotion/react';

Ensure that emotion's cache is server-side rendered and rehydrated using Chakra's SSR utilities.

2. Use Chakra's SSR Support Properly

// lib/createEmotionCache.ts
export default function createEmotionCache() {
  return createCache({ key: 'chakra', prepend: true });
}

Pass this cache to ChakraProvider and emotion cache provider in both _app and _document.

3. Insert ColorModeScript in Document

// pages/_document.tsx
<ColorModeScript initialColorMode={theme.config.initialColorMode} />

Place this as the first child inside the <body> tag to avoid flashing default color mode styles.

4. Avoid Client-only Logic in Render Path

Move any browser-based conditional logic (e.g., layout changes based on screen size) into useEffect blocks or wrap them in typeof window !== 'undefined'.

5. Stabilize Component Keys and Layouts

Ensure consistent component structure between renders and always provide stable key props when using lists or conditionally rendered components.

Best Practices

  • Always include ColorModeScript with correct theme config
  • Use ChakraProvider and CacheProvider together for SSR
  • Preload fonts and theme tokens where possible
  • Avoid layout-affecting JS in the first render pass
  • Test pages with and without JS to compare SSR fidelity

Conclusion

Hydration mismatch and layout instability in Chakra UI are often caused by inconsistent SSR setups and improper rendering practices. By stabilizing the styling pipeline using Chakra's SSR tools, ensuring proper theme and color mode initialization, and minimizing render-time divergence, developers can build responsive, accessible, and high-performance UIs with Chakra. In enterprise-grade apps, predictable rendering is key to both UX and maintainability.

FAQs

1. Why do I see layout shifts after hydration with Chakra UI?

It usually means Chakra styles or theme tokens weren't properly injected during SSR. Ensure emotion cache and color mode scripts are configured correctly.

2. What causes "Text content did not match" in Next.js + Chakra?

It's a hydration mismatch—your SSR HTML differs from the client-rendered version, often due to dynamic content or missing Chakra SSR config.

3. Do I need to customize _document.js with Chakra?

Yes. You must include ColorModeScript and emotion style tags for SSR support to prevent layout flash and CSS duplication.

4. How do I prevent flickering between light and dark mode?

Use ColorModeScript with the correct initial color mode in _document. Ensure hydration uses the same theme config.

5. Can I use Chakra UI without SSR?

Yes, but for Next.js and SEO-heavy apps, SSR is recommended. Chakra supports both modes with appropriate setup.