Optimization Techniques

Improving the performance of a web application involves a combination of strategies that target load time, runtime efficiency, and resource usage. Below are key techniques you can apply to most projects.

1. Minify & Compress Assets

Reduce the size of CSS, JavaScript, and HTML files with minification tools (e.g., uglify-js, csso) and enable gzip or brotli compression on the server.

2. Image Optimization

Serve images in modern formats (WebP, AVIF), use responsive srcset, and apply lossless compression via tools like imagemin.

3. HTTP/2 & HTTP/3

Leverage multiplexing, header compression, and server push to reduce round‑trips. Ensure your server supports these protocols.

4. Caching Strategies

Implement both client‑side (Cache‑Control, ETag) and server‑side caching (Redis, Varnish). Use service workers for offline capabilities.

5. Lazy Loading & Code Splitting

Defer loading of non‑critical resources. In JavaScript, split bundles with dynamic import() or tools like Webpack’s SplitChunksPlugin.

6. Critical Rendering Path

Inline critical CSS, defer non‑essential scripts, and place CSS before JS in the <head> to avoid render‑blocking.

7. Reduce JavaScript Execution Time

Avoid long tasks, use web workers for heavy computation, and adopt modern APIs (e.g., requestIdleCallback).

8. Optimize Fonts

Load only required font weights, use font-display: swap, and preload critical fonts.

9. Server‑Side Rendering (SSR) & Static Generation

Render pages on the server for faster Time‑to‑First‑Byte (TTFB) and better SEO.

10. Monitoring & Profiling

Use Lighthouse, WebPageTest, and browser DevTools to continuously measure performance and identify bottlenecks.

Example: Copy Code Snippet

function debounce(fn, delay) {
  let timeout;
  return (...args) => {
    clearTimeout(timeout);
    timeout = setTimeout(() => fn.apply(this, args), delay);
  };
}