aFarkas/lazysizes

Health v2 · maintenance only

Adoption not part of the score

17718 stars · 1690 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

lazysizes is a high-performance, SEO-friendly lazy loader for images (including responsive picture/srcset), iframes, scripts, and widgets. It self-initializes without configuration, detects visibility changes from user interaction, CSS, or JavaScript, and can automatically calculate the sizes attribute for responsive images.

Use cases

• lazy load images on a webpage to improve page speed
• defer loading of YouTube or Vimeo iframes until scrolled into view
• implement responsive images with automatic sizes calculation
• lazy load widgets and scripts embedded in a page
• improve perceived performance by prioritizing in-view and near-view resources
• add lazy loading to a site without writing JavaScript configuration

When to choose

• you need a zero-configuration, drop-in lazy loader for images and iframes
• you want SEO-friendly lazy loading that works without JavaScript setup
• you need automatic sizes attribute calculation for responsive images
• you want jank-free scrolling performance while lazy loading

When to avoid

• you only target modern browsers and prefer native loading="lazy" attributes
• you need lazy loading for non-DOM content like data or modules
• your project requires a framework-integrated lazy loading solution with React/Vue components

Facets

library · maturity maintenance

image-processing developer-tools web-development frontend performance browser lazy-loading responsive-images seo srcset intersection-observer vanilla-js nodejs

Member repositories

For agents

markdown · JSON · MCP: product_card(name="aFarkas/lazysizes")