DEV Community: hwlsniper

The Privacy Test Every PDF User Should Run

hwlsniper — Mon, 15 Jun 2026 05:26:38 +0000

The Privacy Test Every PDF User Should Run

Open any "free online PDF tool." Drop in a document. Open DevTools → Network tab.

You just sent your file to a server.

For most documents this is fine. For tax returns, signed contracts, or medical records — it's not.

The Test

Try this with the top 5 Google results for "compress pdf online":

Upload a PDF
Watch the Network tab
See your file sent via POST to an unknown server

The privacy policies tell you what happens next:

Smallpdf: deleted after 1 hour
iLovePDF: deleted after "a few hours"
Some services claim rights to "analyze your content"

The Alternative

PDF Toolbox does all processing in your browser using WebAssembly. Open DevTools, use any tool, and watch: zero network requests after page load.

Compress, merge, split, convert PDFs
PDF to Word, PDF to JPG, protect/unlock
No signup, no limits, no tracking
Works offline after page load

Why This Matters Now

AI companies are scraping the web for training data. PDF tools that store your files on their servers — even temporarily — create another vector for your data to end up in training sets you never consented to.

Browser-based processing eliminates this risk entirely. If the file never leaves your device, it cannot be scraped, leaked, or analyzed.

Try the test yourself: pdftoolbox.tech

Source: github.com/hwlsniper/pdftoolbox

I Built a PDF Toolbox That Never Uploads Your Files — Here's How

hwlsniper — Mon, 15 Jun 2026 04:37:12 +0000

Every "free online PDF tool" uploads your files to a server. I built one that doesn't — and here's the technical breakdown.

The Privacy Problem

Try this: Google "compress pdf online free" and use the first 5 results. Each one uploads your PDF to their server, processes it, and gives you a download link. Your file sits on their server — anywhere from 1 hour to 14 days.

The privacy policies tell the story:

Smallpdf: "We retain your files for 1 hour"
iLovePDF: Files deleted after "a few hours"
Adobe: "We may process your files to improve our services"

For contracts, tax forms, or medical records — this is a privacy disaster.

The Architecture: Client-Side PDF Processing

The core insight: you don't need a server to process PDFs. Everything can happen in the browser.

Tech stack:

Next.js 16 — React framework, static generation
pdf-lib — Pure JavaScript PDF manipulation library
WebAssembly — Near-native performance for heavy operations
Tailwind CSS — Responsive UI

The Processing Pipeline

User drops file → FileReader → ArrayBuffer
    → pdf-lib processes in memory  
    → new PDF blob → URL.createObjectURL()
    → download starts

No fetch(), no XMLHttpRequest, no FormData. The file never leaves the JavaScript heap.

pdf-lib: The Engine

pdf-lib can create and modify PDFs entirely in memory. It supports merging, splitting, compressing, password protection, page rotation, and font embedding — all without native dependencies.

Verify It Yourself

Open DevTools Network tab. Use any tool on the site. You'll see:

Initial page load (HTML/CSS/JS)
That's it.

No POST requests. No WebSocket uploads. The tools even work offline — disconnect your internet after page load and everything still functions.

What This Enables

When files never leave the browser:

No file size limits — bounded only by device memory
No account required — nothing to track, nothing to rate-limit
Instant processing — no upload wait time
True privacy — zero data retention, zero content analytics

The Trade-offs

Very large PDFs (500MB+) can slow down the browser
OCR requires Tesseract.js WebAssembly (heavy initial load, 2MB+)
Some features (digital signatures, advanced form filling) are complex client-side

Why I Built This

Most PDF tools treat privacy as an afterthought — they add a "we delete your files after X hours" banner and call it a day. But privacy shouldn't be a footnote. It should be the architecture.

Building everything client-side was harder. But asking users to trust a server they can't verify isn't acceptable for sensitive documents.

Try It

The site is free, no signup required: pdftoolbox.tech

Source code: github.com/hwlsniper/pdftoolbox

Would love feedback from the Dev.to community. What other PDF operations would you want to see done entirely client-side?

I Built a Privacy-First PDF Toolbox — Your Files Never Leave the Browser

hwlsniper — Sun, 14 Jun 2026 06:06:02 +0000

The Problem

Every time I needed to compress a PDF or convert it to JPG, I had to upload my files to some random server. Tax documents, contracts, personal records — all sent to who-knows-where.

So I built PDF Toolbox — a free, browser-based PDF toolkit that does everything locally.

How It Works

All processing happens right in your browser using WebAssembly and pdf-lib:

No file uploads — your files never leave your device
No registration — just open and use
No daily limits — use it as much as you want
8 tools — Compress, Merge, Split, PDF→JPG, JPG→PDF, PDF→Word, Unlock, Protect

Why Client-Side Matters

Most free PDF tools either:

Upload your files to process server-side (privacy risk)
Watermark your output
Limit you to 2 files per day

PDF Toolbox does none of that. The code runs entirely in your browser, so sensitive documents stay on your device.

Tech Stack

Next.js 16 + React
pdf-lib for PDF manipulation
WebAssembly for compression
Zero server processing — everything client-side

Try It

Check it out at pdftoolbox.tech. Completely free, no signup needed.

Feedback welcome — what PDF features would you want next?

I Built a Privacy-First PDF Toolbox That Runs Entirely in Your Browser

hwlsniper — Sun, 14 Jun 2026 05:44:07 +0000

The Problem

Every time I needed to compress a PDF or convert it to JPG, I had to upload my files to some random server. Tax documents, contracts, personal records — all sent to who-knows-where.

So I built PDF Toolbox — a free, browser-based PDF toolkit that does everything locally.

How It Works

All processing happens right in your browser using WebAssembly and pdf-lib:

No file uploads — your files never leave your device
No registration — just open and use
No daily limits — use it as much as you want
8 tools — Compress, Merge, Split, PDF→JPG, JPG→PDF, PDF→Word, Unlock, Protect

Why Client-Side Matters

Most free PDF tools either:

Upload your files to process server-side (privacy risk)
Watermark your output
Limit you to 2 files per day

PDF Toolbox does none of that. The code runs entirely in your browser, so sensitive documents stay on your device.

Tech Stack

Next.js 16 + React
pdf-lib for PDF manipulation
WebAssembly for compression
Zero server processing — everything client-side

Try It

Check it out at pdftoolbox.tech. Completely free, no signup needed.

Feedback welcome — what PDF features would you want next?

I Built a Privacy-First PDF Toolbox — Your Files Never Leave the Browser

hwlsniper — Sun, 14 Jun 2026 03:45:45 +0000

Every online PDF tool I've used uploads your documents to their servers. Tax returns, contracts, medical records — they all go to some third-party server for processing. That bothered me enough to build an alternative.

PDF Toolbox is a set of PDF tools where everything runs locally in your browser.

How it works

You select a PDF file
The file loads into browser memory (ArrayBuffer)
pdf-lib processes it entirely in the browser
You download the result

The file never leaves your computer. No upload. No server. No privacy risk.

Features

Compress PDF — reduce file size without quality loss
Merge PDF — combine multiple PDFs into one
Split PDF — extract individual pages
PDF to JPG — convert pages to images
JPG to PDF — create PDFs from images
Unlock PDF — remove password protection

Why I built it

I handle sensitive documents regularly and the thought of uploading them to random servers makes me uncomfortable. With WebAssembly and modern PDF libraries like pdf-lib, there's no technical reason PDF tools need server-side processing anymore.

Tech Stack

Next.js 16 with App Router
pdf-lib for PDF generation and manipulation
pdfjs-dist for PDF rendering
Tailwind CSS 4 for styling
Vercel for hosting

Try it out

PDF Toolbox — completely free, no registration, no limits.

GitHub Repo

Feedback and feature requests welcome!

I Built a Privacy-First PDF Toolbox — Your Files Never Leave the Browser

hwlsniper — Fri, 12 Jun 2026 02:52:25 +0000

PDF Toolbox is a set of PDF tools where everything runs locally in your browser.

How it works

You select a PDF file
The file loads into browser memory (ArrayBuffer)
pdf-lib processes it entirely in the browser
You download the result

The file never leaves your computer. No upload. No server. No privacy risk.

Features

Compress PDF — reduce file size while keeping quality
Merge PDFs — combine multiple files into one document
Split PDF — extract pages or split into separate files
PDF to JPG — convert pages to high-quality images
JPG to PDF — turn images into a PDF document
Unlock PDF — remove password protection

Why I built it

Most online PDF tools (SmallPDF, iLovePDF, etc.) upload your files to their servers. That means your contracts, tax documents, and personal records sit on someone else's infrastructure. PDF Toolbox eliminates that risk entirely.

Tech Stack

Next.js 16 with App Router
pdf-lib for PDF generation and manipulation
pdfjs-dist for PDF rendering
Tailwind CSS 4 for styling
Vercel for hosting

The entire processing pipeline runs client-side. Zero server costs for file processing, zero privacy concerns, and no file size limits imposed by a server.

Try it out

PDF Toolbox — completely free, no registration, no limits.

Source code on GitHub. Feedback and feature requests welcome!

I Built a Free PDF Toolbox That Runs Entirely in Your Browser (Zero Uploads)

hwlsniper — Tue, 26 May 2026 15:17:12 +0000

Why I Built It

I needed to compress a PDF last week. The first 5 Google results all required uploading my file to a server. Some wanted my email. Others limited me to 2 files per day.

I'm a developer. I thought: we have WebAssembly, Web Workers, and the File API — why are we still uploading PDFs to random servers?

So I built PDF Toolbox — a collection of PDF tools that process everything locally in your browser.

What It Does

Compress PDF — reduce file size while keeping quality
Merge PDF — combine multiple PDFs into one
Split PDF — extract pages or split into individual files
PDF to JPG — convert each page to an image
JPG to PDF — bundle images into a PDF
Unlock PDF — remove password protection (if you know the password)

Tech Stack

Built with Next.js 16 + TypeScript + Tailwind CSS, deployed on Vercel. The PDF processing uses client-side libraries so files never touch a server. Every tool works offline once the page is loaded.

Design Decisions

Privacy-first architecture

This was my number one constraint. All PDF processing runs in the browser using the Web Worker API. When you drop a file, it stays in your browser's memory — nothing is sent to any backend. You can turn off your internet connection after the page loads and everything still works.

No limits, no registration

Most PDF tools gate features behind accounts or daily limits. PDF Toolbox has no concept of users — there's no database, no login, no tracking. Use it as many times as you want.

Simple UI, complex backend

I kept the interface dead simple: drag-and-drop, one-click processing, instant download. But under the hood there's a lot going on — streaming file reads, memory-efficient processing for large PDFs, and proper error handling for edge cases like encrypted files and corrupted PDFs.

What's Next

PDF to Word — coming soon
Watermark PDF — add text/image watermarks
Dark mode — working on it
Mobile PWA — installable offline app

Try It Out

Head over to pdftoolbox-three.vercel.app and try compressing a PDF. No signup, no upload, no catch.

I'd love feedback from the Dev.to community! What PDF features would you find most useful? Drop a comment below.

I Built a Privacy-First PDF Toolbox — Your Files Never Leave the Browser

hwlsniper — Tue, 26 May 2026 13:04:15 +0000

PDF Toolbox is a set of PDF tools where everything runs locally in your browser.

How it works

You select a PDF file
The file loads into browser memory (ArrayBuffer)
pdf-lib processes it entirely in the browser
You download the result

The file never leaves your computer. No upload. No server. No privacy risk.

Features

Compress PDF (reduce file size)
Merge multiple PDFs into one
Split PDF into individual pages
Convert PDF to JPG images
Convert JPG images to PDF
Unlock password-protected PDFs

Why I built it

Tech Stack

Next.js 16 with App Router
pdf-lib for PDF generation and manipulation
pdfjs-dist for PDF rendering
Tailwind CSS 4 for styling
Vercel for hosting

Try it out

PDF Toolbox — completely free, no registration, no limits.

Feedback and feature requests welcome!

GitHub: github.com/hwlsniper/pdftoolbox