PDF.js Browser PDF Viewer

PDF.js is a web standards-based platform for parsing and rendering PDF documents, developed by Mozilla as the built-in PDF viewer for Firefox and adopted across the web ecosystem. Originally created by Chris Jones in 2011 as an experiment to prove that PDFs could be rendered entirely in HTML5 Canvas without native plugins, the project became the default PDF viewer in Firefox 15 and now powers document viewing for millions of daily users. The library provides two main components: the core API that handles PDF parsing, font embedding, and text extraction, and a reference viewer that offers navigation, search, thumbnail sidebar, zoom, page rotation, and annotation rendering. The rendering pipeline processes the PDF binary format through a JavaScript-based parser, reconstructs the page content tree, resolves embedded fonts via a custom font mapping engine, and draws each page to an HTML5 Canvas element or through a text layer for accessibility. The text layer extraction enables copy-paste, search, and screen reader compatibility that native PDF viewers often lack. PDF.js handles complex PDF features including encrypted documents, digital signatures, form fields, rich media annotations, and layered content. The library is maintained by Mozilla as an Apache 2.0 licensed open source project with active contributions from Google Chrome engineers and the broader web community. Beyond Firefox, it powers the document viewers in VS Code, Slack, Dropbox, GitHub, and numerous enterprise applications.