Browser-First PDF Manipulation: No Server Required

Why Server-Side PDF Processing Is a Problem

PDF manipulation is among the most privacy-sensitive operations a web user can perform. Merging legal contracts, splitting financial statements, compressing tax returns — these files contain some of the most personal data imaginable.

Yet nearly every popular PDF tool (Smallpdf, ILovePDF, PDF24) uploads your documents to European or American cloud servers, processes them there, and promises to delete them "within a few hours." You're trusting their word — and their security posture — with your most sensitive documents.

ElevenTools PDF Tools takes a fundamentally different approach. Your PDFs never leave your device.

The PDF Stack: pdf-lib + PDF.js

PDF Tools relies on two battle-tested open-source libraries:

Merging PDFs

import { PDFDocument } from 'pdf-lib';

async function mergePDFs(files: File[]): Promise {
  const mergedPdf = await PDFDocument.create();

  for (const file of files) {
    const arrayBuffer = await file.arrayBuffer();
    const doc = await PDFDocument.load(arrayBuffer);
    const copiedPages = await mergedPdf.copyPages(doc, doc.getPageIndices());
    copiedPages.forEach(page => mergedPdf.addPage(page));
  }

  return mergedPdf.save();
}

This merges arbitrary numbers of PDFs in pure JavaScript. Memory usage scales with the total size of input documents, which is why PDF Tools enforces a 50MB combined limit on the free tier.

Splitting PDFs

async function splitPDF(file: File, ranges: [number, number][]): Promise {
  const arrayBuffer = await file.arrayBuffer();
  const srcDoc = await PDFDocument.load(arrayBuffer);

  return Promise.all(ranges.map(async ([start, end]) => {
    const newDoc = await PDFDocument.create();
    const pages = await newDoc.copyPages(srcDoc, 
      Array.from({ length: end - start + 1 }, (_, i) => start + i - 1)
    );
    pages.forEach(p => newDoc.addPage(p));
    return newDoc.save();
  }));
}

Compression via Re-encoding

True PDF compression (removing embedded fonts, optimizing streams) is complex. PDF Tools currently offers "compression" by re-saving with pdf-lib's optimization flags, which removes redundant metadata and can reduce file size by 10–40% depending on the source document.

The Privacy Guarantee

PDF Tools is built on an inviolable constraint: the server never sees your files. This isn't just aspirational — Cloudflare Workers, our edge runtime, has no upload endpoints for PDF Tools. The architecture enforces privacy.

Try PDF Tools at /pdf-tools.