AIToolly product video
Pretext - Text measurement that never touches the DOM.
Pretext.js is a revolutionary JavaScript library designed for high-performance text measurement and layout. Unlike traditional methods that rely on the browser's DOM and cause expensive reflows, Pretext.js uses pure arithmetic and Canvas-based glyph measurement to calculate text height and line counts. This approach is up to 500x faster, making it ideal for performance-critical applications like virtual scrolling, AI chat interfaces, and complex multilingual feeds. Written in TypeScript with zero runtime dependencies, Pretext.js ensures 60fps smooth rendering by eliminating forced synchronous reflows and layout thrashing.
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Text measurement without touching the DOM.
Meet Pretext, built for complex, text-heavy interfaces.
It lays out 1,000 blocks for a clear performance demonstration.
Measure once, then lay out forever.
Pretext compares traditional DOM measurement with a Canvas-based approach.
It uses real font metrics and supports multilingual text by design.
With zero DOM reads, it targets performance-critical cases.
TypeScript-native, dependency-free, and built around reusable prepared handles.
Try Pretext today and explore what developers are building.
