---
title: Mobile Performance Patterns
created: 2026-07-03
updated: 2026-07-03
type: system
tags: [mobile, performance, core-web-vitals, lcp, inp, cls, optimization]
sources:
  - https://developers.google.com/search/docs/appearance/core-web-vitals
  - https://rankture.com/blog/core-web-vitals-optimization-guide
  - https://eastondev.com/blog/en/posts/dev/20251124-core-web-vitals-optimization/
  - https://ubmetrics.com/blog/core-web-vitals-complete-guide-2025
  - https://www.airankaudit.com/core-web-vitals-guide-2025-lcp-inp-cls-explained-with-fixes/
confidence: high
---

# Mobile Performance Patterns — Производительность для мобильных

## 1. Core Web Vitals: Мобильные Стандарты 2025/2026

### 1.1 Thresholds

| Метрика | Good | Needs Improvement | Poor |
|---------|------|-------------------|------|
| **LCP** | ≤ 2.5s | 2.5s - 4.0s | > 4.0s |
| **INP** | ≤ 200ms | 200ms - 500ms | > 500ms |
| **CLS** | ≤ 0.1 | 0.1 - 0.25 | > 0.25 |

### 1.2 Mobile-First Importance

На мобильных:
- LCP **критичнее** из-за медленных сетей (3G/4G)
- INP **критичнее** из-за более слабых CPU
- CLS **критичнее** из-за smaller viewport и layout shifts

### 1.3 Measurement Tools

| Tool | Purpose | Best For |
|------|---------|----------|
| PageSpeed Insights | Lab + Field Data | Quick audit |
| Chrome UX Report | Real user data | Production monitoring |
| Web Vitals JS Library | Runtime measurement | Dev instrumentation |
| Lighthouse | Lab testing | Development |
| DevTools Network Throttling | Simulated 3G | Testing |

## 2. Largest Contentful Paint (LCP)

### 2.1 What is LCP?

Время, когда **крупнейший элемент контента** (hero image, H1, section) становится видимым.

### 2.2 LCP Optimization Checklist

```
Priority:
1. Critical image — preload + next-gen format
2. Above-the-fold content — inline critical CSS
3. Server response — reduce TTFB
4. Render-blocking resources — defer/async
5. JS execution — minify + code split
```

### 2.3 Critical Image Optimization

```html
<!-- Hero image: preload as resource -->
<link rel="preload" as="image" href="/hero-large.webp" fetchpriority="high">

<!-- Responsive hero with next-gen formats -->
<picture>
  <source srcset="hero-480.webp 480w, hero-800.webp 800w, hero-1200.webp 1200w"
          media="(min-width: 768px)">
  <img
    src="hero-480.webp"
    loading="eager"
    fetchpriority="high"
    decoding="async"
    width="800"
    height="600"
    alt="Hero description"
    class="lcp-hero"
  >
</picture>
```

```css
/* Prevent layout shift for LCP image */
.lcp-hero {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
  background: color-mix(in srgb, var(--surface-2) 50%, transparent);
}
```

### 2.4 Critical CSS Inlining

```html
<head>
  <!-- Inline critical CSS (above-the-fold) -->
  <style>
    /* Critical path CSS — target < 14KB gzipped */
    .hero {
      min-height: 60vh;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      padding: 24px 16px;
    }
    .hero__title {
      font-size: clamp(2rem, 8vw, 4rem);
      line-height: 1.1;
      margin-bottom: 16px;
    }
    /* ... more critical styles ... */
  </style>
  
  <!-- Defer non-critical CSS -->
  <link rel="preload" href="/styles.css" as="style" onload="this.onload=null;this.rel='stylesheet'">
  <noscript><link rel="stylesheet" href="/styles.css"></noscript>
</head>
```

### 2.5 Reduce TTFB (Time to First Byte)

```
Optimization:
1. Use CDN (Cloudflare, Fastly, AWS CloudFront)
2. Edge caching (Vercel, Netlify Edge, Cloudflare Workers)
3. HTTP/2 or HTTP/3
4. Database query optimization
5. Server-side rendering (SSR) or static generation
6. Connection pooling
```

## 3. Interaction to Next Paint (INP)

### 3.1 What is INP?

Время между **пользовательским взаимодействием** и следующей отрисовкой. Заменяет FID (First Input Delay).

### 3.2 INP Optimization Strategies

```javascript
// 1. Use passive event listeners
document.addEventListener('scroll', handler, { passive: true });
document.addEventListener('touchstart', handler, { passive: true });

// 2. Debounce expensive operations
function debounce(fn, delay = 16) {
  let ticking = false;
  return () => {
    if (!ticking) {
      requestAnimationFrame(() => {
        fn();
        ticking = false;
      });
      ticking = true;
    }
  };
}

// 3. Offload heavy work to Web Workers
// worker.js
self.onmessage = (e) => {
  const result = heavyComputation(e.data);
  self.postMessage(result);
};
```

```css
/* 4. GPU-accelerated animations */
.animated-element {
  will-change: transform, opacity;
  transform: translateZ(0);
}

/* 5. Avoid layout thrashing */
// Bad: forces layout recalculation
element.style.width = '100px';
console.log(element.offsetWidth);

// Good: batch reads
const width = element.offsetWidth; // read
element.style.width = '100px';     // write
```

### 3.3 INP Debugging Checklist

| Category | Check | Tool |
|----------|-------|------|
| **Event handlers** | Passive listeners where possible | DevTools |
| **Long tasks** | < 50ms per task | DevTools Long Tasks |
| **JS execution** | Code splitting, tree shaking | Lighthouse |
| **Layout thrashing** | Batch reads/writes | DevTools |
| **Main thread** | No blocking scripts | Performance panel |

## 4. Cumulative Layout Shift (CLS)

### 4.1 What is CLS?

Суммарный сдвиг **всех визуальных элементов** за время загрузки страницы.

### 4.2 CLS Prevention Patterns

```css
/* 1. Always set dimensions on images/videos */
img, video, iframe {
  width: 100%;
  height: auto;
  object-fit: cover;
}

/* 2. Reserve space for dynamic content */
.ad-container {
  min-height: 200px;
  background: var(--surface-2);
}

/* 3. Font loading — prevent FOIT/FOUT */
@font-face {
  font-family: 'MyFont';
  src: url('/fonts/myfont.woff2') format('woff2');
  font-display: swap;
}

/* 4. Sticky ads — fixed position */
.ad-sticky {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
}

/* 5. Skeleton loaders */
.skeleton {
  background: linear-gradient(90deg, var(--surface-2) 25%, var(--surface-3) 50%, var(--surface-2) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: 4px;
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}
```

### 4.3 CLS Measurement

```javascript
// Web Vitals library for CLS
import { getCLS } from 'web-vitals';

getCLS((value) => {
  console.log('CLS:', value);
  // Report to analytics
  if (value > 0.25) {
    sendToAnalytics('cls_threshold_exceeded', { value });
  }
});
```

## 5. Image Optimization

### 5.1 Image Strategy for Mobile

```
Priority:
1. Use next-gen formats (WebP, AVIF)
2. Responsive images with srcset
3. Lazy loading for below-fold images
4. Proper dimensions (width/height)
5. Compress images (Squoosh, TinyPNG)
6. CDN for image delivery
```

### 5.2 Responsive Images Pattern

```html
<picture>
  <source srcset="image-small.webp 400w, image-medium.webp 800w, image-large.webp 1200w"
          media="(min-width: 768px)">
  <source srcset="image-small.avif 400w, image-medium.avif 800w, image-large.avif 1200w"
          media="(min-width: 768px)">
  <img
    src="image-small.webp"
    srcset="image-small.webp 400w, image-medium.webp 800w, image-large.webp 1200w"
    sizes="(max-width: 767px) 100vw, 50vw"
    loading="lazy"
    decoding="async"
    width="800"
    height="600"
    alt="Description"
    class="lazy-image"
  >
</picture>
```

### 5.3 Lazy Loading with Intersection Observer

```javascript
class LazyLoader {
  constructor(options = {}) {
    this.threshold = options.threshold || 0.1;
    this.rootMargin = options.rootMargin || '200px 0px';
    this.observer = new IntersectionObserver((entries) => {
      entries.forEach(entry => {
        if (entry.isIntersecting) {
          const el = entry.target;
          
          if (el.tagName === 'IMG') {
            if (el.dataset.src) el.src = el.dataset.src;
            if (el.dataset.srcset) el.srcset = el.dataset.srcset;
          }
          
          if (el.tagName === 'VIDEO') {
            if (el.dataset.src) el.src = el.dataset.src;
          }
          
          el.classList.add('loaded');
          this.observer.unobserve(el);
        }
      });
    }, {
      threshold: this.threshold,
      rootMargin: this.rootMargin
    });
  }
  
  observe(elements) {
    elements.forEach(el => this.observer.observe(el));
  }
}

// Usage
const lazyLoader = new LazyLoader({ rootMargin: '200px 0px' });
document.querySelectorAll('.lazy').forEach(el => lazyLoader.observe(el));
```

## 6. CSS & JS Optimization

### 6.1 CSS Optimization

```css
/* 1. Use CSS containment */
.contained {
  contain: layout style paint;
}

/* 2. Minimize reflows */
.element {
  will-change: transform;
  transform: translateZ(0);
}

/* 3. Use CSS variables for theming (avoids JS) */
:root {
  --primary: #0070f3;
  --text-primary: #111;
}
```

### 6.2 JavaScript Optimization

```javascript
// 1. Code splitting
const lazyModule = import('./heavy-module.js');

// 2. Debounce user input
function debounce(fn, delay = 16) {
  let ticking = false;
  return () => {
    if (!ticking) {
      requestAnimationFrame(() => {
        fn();
        ticking = false;
      });
      ticking = true;
    }
  };
}

// 3. Virtual scroll for long lists
function virtualScroll(container, items, itemHeight) {
  const visibleCount = Math.ceil(container.clientHeight / itemHeight);
  const scrollTop = container.scrollTop;
  const startIndex = Math.floor(scrollTop / itemHeight);
  const endIndex = Math.min(startIndex + visibleCount + 10, items.length);
  
  // Only render visible items
  for (let i = startIndex; i < endIndex; i++) {
    renderItem(items[i]);
  }
}

// 4. Use requestAnimationFrame for animations
function animateElement(element, keyframes, options) {
  element.animate(keyframes, {
    ...options,
    fill: 'forwards'
  });
}
```

## 7. Network Optimization

### 7.1 Service Worker Caching

```javascript
// sw.js
const CACHE_NAME = 'mobile-app-v1';
const ASSETS_TO_CACHE = [
  '/',
  '/styles.css',
  '/app.js',
  '/fonts/*'
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(ASSETS_TO_CACHE))
  );
});

self.addEventListener('fetch', (event) => {
  event.respondWith(
    caches.match(event.request).then((response) => {
      return response || fetch(event.request);
    })
  );
});
```

### 7.2 Prefetch & Preconnect

```html
<!-- Preconnect to critical origins -->
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="preconnect" href="https://api.example.com">

<!-- Prefetch critical resources -->
<link rel="prefetch" href="/next-page.js">
<link rel="prefetch" href="/critical-image.webp">

<!-- Preload critical resources -->
<link rel="preload" href="/hero-large.webp" as="image" fetchpriority="high">
```

## 8. Mobile Performance Checklist

| Metric | Target | Tool |
|--------|--------|------|
| **LCP** | ≤ 2.5s | PageSpeed Insights |
| **INP** | ≤ 200ms | Web Vitals JS |
| **CLS** | ≤ 0.1 | PageSpeed Insights |
| **FCP** | ≤ 1.8s | DevTools |
| **TTFB** | ≤ 600ms | Network panel |
| **Total JS** | ≤ 200KB | Lighthouse |
| **Total CSS** | ≤ 50KB (critical) | Lighthouse |
| **Images** | Next-gen + responsive | PageSpeed Insights |

## 9. Mobile Performance Anti-Patterns

| ❌ Плохо | ✅ Хорошо |
|----------|-----------|
| 100vh для полноэкранных секций | 100dvh |
| Полноэкранные изображения | Responsive images + lazy loading |
| Тяжелые JS-библиотеки | Vanilla JS / lightweight alternatives |
| Автоплей видео | Play/pause по тапу |
| Шрифты без font-display | font-display: swap |
| Без сжатия изображений | WebP/AVIF + compression |
| Синхронный JS в <head> | Async/defer |