Split PDF Pages in the Browser with pdf-lib — No Uploads, No Server
A few weeks ago I built a free online Merge PDF tool that runs 100% in the browser. Today I'm sharing its sibling: a Split PDF tool using the same library — pdf-lib — with zero file uploads, zero watermark, and zero server code. You can try it live here: https://yourutilityhub.com/pdf/split-pdf Why split PDFs in the browser? Most online PDF tools upload your file to a server — which means your document is never truly private. Splitting pages locally means: No uploads — nothing leaves your device No watermark or signup Free — no per-page charges Works offline, fast, for files of any size (limited by your browser's memory) The plan We'll load the PDF, pick a page range (or specific pages), copy those pages into a fresh PDFDocument , and save the result — all with pdf-lib . Let's walk through the full working component . 1. Install and import npm install pdf-lib import { PDFDocument } from " pdf-lib " ; 2. Load the uploaded file const arrayBuffer = await file . arrayBuffer (); const pdf = await PDFDocument . load ( arrayBuffer ); const totalPages = pdf . getPageCount (); PDFDocument.load() accepts an ArrayBuffer . We read it straight from the File object — no server involved. 3. Split by page range (e.g. 1-5 or 3- ) const parts = pageRange . split ( " - " ); const startRaw = parseInt ( parts [ 0 ]. trim (), 10 ); const endRaw = parts [ 1 ]. trim () === "" ? totalPages : parseInt ( parts [ 1 ]. trim (), 10 ); // validate 1..totalPages const startPage = Math . min ( startRaw , endRaw ) - 1 ; // 0-based const endPage = Math . max ( startRaw , endRaw ) - 1 ; const newPdf = await PDFDocument . create (); const pageIndices = []; for ( let i = startPage ; i <= endPage ; i ++ ) { pageIndices . push ( i ); } const copiedPages = await newPdf . copyPages ( pdf , pageIndices ); copiedPages . forEach ( page => newPdf . addPage ( page )); The trick: copyPages() wants 0-based indices , but users type 1-based page numbers, so we subtract 1. "3-" with an empty end means "to the last pa