I Built 30+ Free Web Tools with Zero Server Uploads (100% Client-Side)

#webdev #javascript #privacy #opensource

Most online utility sites (PDF converters, image optimizers, file format converters) force you to do two things I really dislike:

Upload private documents (contracts, invoices, ID cards, tax receipts) to unknown third-party cloud servers.
Hit a paywall or forced registration after just 2 basic conversions.

So I decided to build MiniTools (https://getminitools.com) — a suite of 30+ web tools designed with a strict Zero-Server Client-Side architecture.

🔒 How it Works Under the Hood

Instead of sending your files across the internet to a backend worker, MiniTools performs every operation directly inside your browser memory:

PDF Manipulation: Merging, splitting, rotating, and compressing PDF files runs locally using pdf-lib and modern WebAssembly.
Image Optimization: Binary-search canvas compression algorithms that reduce photos to exact file size limits (e.g. strict 30KB / 50KB limits required for government and visa portals).
Fast Format Converters: HEIC to JPG, WebP to PNG/JPG, PNG to JPG without touching a server.
Business & Math Calculators: Multi-country VAT/Tax breakdown, business days counter (excluding weekends), rule of three proportions, and percentage calculators.
PWA & Offline Ready: Service worker caching ensures that once loaded, you can use these tools even on an airplane with zero internet connection.

🛠️ The Tool Suite

You can explore the full collection here: https://getminitools.com

📄 PDF Suite: Merge PDF, Compress PDF, Split PDF, Rotate PDF, PDF to Word (.docx), PDF to JPG.
🖼️ Image Suite: Image Compressor, Compress to 20KB/30KB/50KB, Circular Avatar Crop, Image Resizer, HEIC to JPG, WebP Converter.
🔢 Calculators: VAT/Tax Calculator, Working Days Calculator, Rule of Three, Percentage & Discount Calculators, Age Calculator, Currency Converter.
🛠️ Dev Utilities: Text Diff Checker, JSON Formatter, Base64 Encoder/Decoder, Unix Timestamp, Password Generator, QR Code Generator.