Scanned PDF files, digitized invoices, and image documents are often saved as raw bitmap images, making it impossible to search text with Ctrl+F, highlight sentences, copy data, or use screen readers. This comprehensive guide explains how client-side Optical Character Recognition (OCR) converts scanned image documents into selectable “Sandwich PDFs” by layering an invisible text overlay directly on top of the original visual scan.
WebAssembly and Tesseract.js technology enable 100% private document processing inside your browser without uploading sensitive financial or legal files to remote cloud servers. Access the free RiazHub Make PDF Searchable Tool to convert single-page or multi-page documents instantly.
Make PDF Searchable
Convert scanned PDFs and images into searchable, selectable "Sandwich PDFs" directly in your browser. No files uploaded to any server.
Drag & Drop Scanned PDF or Image Here
Supports scanned PDFs, invoices, receipts, PNG, JPG, WEBP formats
Searchable PDF & OCR Technology Guide
A Sandwich PDF combines a visual scan image on top with an invisible, searchable text layer directly underneath. It preserves 100% of your document's original visual layout, stamps, signatures, and paper texture while enabling instant Ctrl+F keyboard searching, text highlighting, copy-pasting, and compatibility with text-to-speech screen readers.
Many invoices, contracts, and certificates contain bi-lingual text (e.g. English and Arabic side by side). You can select both a Primary and Secondary language in the OCR settings to recognize mixed-language documents simultaneously.
This tool runs Tesseract.js and PDF-Lib directly inside your web browser using WebAssembly. Your scanned documents, confidential invoices, ID cards, or legal files are never uploaded to any server or cloud API. All optical character recognition and PDF rebuilding happen locally in your device's memory.