A step-by-step guide to building a browser-based PDF resizer using JavaScript and the pdf-lib library. Covers uploading PDFs, generating page previews, configuring resize settings (preset and custom page sizes, scaling modes, margins), applying the resize operation, and downloading the output. All processing happens client-side, so documents never leave the user's device. Includes code snippets for each stage and practical notes on validation and common mistakes.
Table of contents
Table of ContentsWhy PDF Resizing Is UsefulHow PDF Resizing WorksProject SetupWhat Library Are We Using?Creating the Upload InterfacePreviewing Uploaded PDF PagesConfiguring Resize SettingsApplying the ResizeGenerating the Resized PDFDemo: How the PDF Resize Tool WorksImportant Notes from Real-World UseCommon Mistakes to AvoidConclusion14.1K Impressions