Lector

A headless PDF viewer for React. Compose pages, text selection, search, and annotations into your own reading experience. Lector handles PDF.js rendering and page virtualization; you control the layout and UI.

Documentation · Live demo · npm · Contributing

Get a PDF on screen

Use React 19+. The current source expects pdfjs-dist ^5.5.207. These docs track main; check the releases against your installed package version.

npm install @anaralabs/lector pdfjs-dist@^5.5.207

Copy the PDF.js worker from your app's installed dependency to its public assets. Recopy it whenever you update PDF.js so the runtime and worker versions match.

mkdir -p public/pdfjs
cp node_modules/pdfjs-dist/legacy/build/pdf.worker.min.mjs public/pdfjs/

Put a PDF at public/sample.pdf, then add this browser-rendered component:

import { CanvasLayer, Page, Pages, Root, TextLayer } from "@anaralabs/lector";
import { GlobalWorkerOptions } from "pdfjs-dist/legacy/build/pdf.mjs";
import "pdfjs-dist/web/pdf_viewer.css";

GlobalWorkerOptions.workerSrc = "/pdfjs/pdf.worker.min.mjs";

export default function PDFViewer() {
  return (
    <Root
      source="/sample.pdf"
      style={{ height: 600 }}
      loader={<p role="status">Loading PDF…</p>}
    >
      <Pages>
        <Page>
          <CanvasLayer />
          <TextLayer />
        </Page>
      </Pages>
    </Root>
  );
}

For Next.js, load the viewer through a Client Component using dynamic(..., { ssr: false }); keep PDF.js setup inside the dynamically loaded module. See installation for the full wrapper, Vite worker setup, and deployments below a path prefix.

Root loads the document and provides its state. Pages owns scrolling and clones one Page template for visible pages. CanvasLayer paints the PDF; TextLayer adds selectable text. Give the viewer a definite height and import the PDF.js stylesheet so its layers align.

Build the reader your app needs

Feature	Start here
Toolbar, page input, and layout	Your first viewer
Authenticated URLs, local files, errors, and self-hosted assets	Loading documents
Page navigation and fit width	Navigation, zoom
Page previews	Thumbnails
Text search and highlighted results	Search
Selection and citation regions	Selection, highlights
PDF links and editable form fields	Links, forms
Dark page rendering	Dark mode
Props, hooks, and defaults	API reference

Lector is a toolkit rather than a finished toolbar or a PDF editor. Your app supplies accessible controls, error UI, and storage for user annotations. Search requires embedded text; it does not perform OCR. Custom highlight overlays do not automatically modify the PDF file. See troubleshooting for worker errors, blank pages, and layout issues.

Use with a coding assistant

Connect an MCP client to https://anara.com/lector/mcp using Streamable HTTP, with no API key. It can search and read every guide through tools and resources. See AI agents and MCP for setup and example requests.

For direct fetching, start with llms.txt, read individual Markdown guides, or use the complete documentation. These exports are generated from the same source as the website.

Work on Lector

From the repository root, with Node.js 22.13+ and pnpm 9.5.0:

pnpm install --frozen-lockfile
pnpm --filter @anaralabs/lector build
pnpm --filter docs dev

Open localhost:3000/docs. The docs app uses the local workspace package. For watch mode, validation commands, and testing in another application, read CONTRIBUTING.md.

Acknowledgements

Inspired by react-pdf-headless and pdfreader. Built on PDF.js and React.

License

MIT © Anara