How I Built a Privacy-First Image to PDF Converter in Next.js (Without Uploading Files on server)
When I started building document utilities, I noticed something that bothered me. Most online Image to PDF converters require users to upload their personal images to a server before generating a PDF. For resumes, passports, certificates, invoices, and other sensitive documents, that isn't always ideal. So I decided to build an Image to PDF converter that works entirely in the browser. No server-side file processing. Why Browser-Side Processing? Modern browsers are much more powerful than they w
When I started building document utilities, I noticed something that bothered me.
Most online Image to PDF converters require users to upload their personal images to a server before generating a PDF.
For resumes, passports, certificates, invoices, and other sensitive documents, that isn't always ideal.
So I decided to build an Image to PDF converter that works entirely in the browser.
No server-side file processing.
No file uploads.
Just your browser.
Why Browser-Side Processing?
Modern browsers are much more powerful than they were a few years ago.
Instead of sending images to a backend, everything can be processed locally.
That provides several advantages:
🔒 Better privacy (files stay on your device)
⚡ Faster processing
💰 Lower hosting costs
🌍 Better scalability
📱 Works well on desktop and mobile
For utility websites, this approach is often a better user experience.
Tech Stack
I built the tool using:
Next.js
React
TypeScript
Tailwind CSS
Browser File API
Canvas API
pdf-lib
Everything happens inside the browser.
Features
The latest version includes:
Multiple image upload
Drag & Drop support
Drag-to-reorder pages
Image rotation
A4 & Letter page sizes
Margin settings
Image quality selection
Browser-based PDF generation
Download
Native Share API support (where available)
Biggest Challenges
Generating the PDF wasn't actually the hardest part.
The real challenge was creating a smooth experience that works across different browsers and devices.
Some areas required extra attention:
Handling large, high-resolution images efficiently
Keeping memory usage under control
Maintaining image quality
Supporting mobile browsers
Creating reusable UI components instead of duplicating logic
Those improvements made a much bigger difference than simply adding more features.
What I Learned
One lesson became very clear:
Users value a polished workflow more than a long feature list.
Simple improvements like:
consistent buttons
drag-and-drop uploads
progress indicators
printable layouts
native sharing
can significantly improve the overall experience.
Live Demo
If you'd like to try it yourself:
👉 Image to PDF Tool
https://formatforge.in/tools/image-to-pdf
You can also explore the full collection of browser-based utilities here:
🌐 FormatForge
https://formatforge.in
The platform focuses on browser-based tools for:
PDF
Images
JSON
YAML
Developer Utilities
Business & Productivity
I'd Love Your Feedback
I'm continuing to improve FormatForge with a focus on:
Performance
Privacy
Browser-first processing
Better developer and user experience
I'm curious:
Do you prefer browser-side or server-side document processing?
Which PDF library has worked best for your projects?
What's one feature you think every PDF tool should include?
I'd love to hear your thoughts and suggestions in the comments.
