The Frustration That Started It All
It was a late night in March 2026. I needed to compress a PDF. Simple, right?
Nope. The first site hit me with a 30-second ad. The second wanted me to "download our free software" (spoiler: it wasn't free). The third uploaded my file to god-knows-where. I closed my laptop, stared at the ceiling, and thought:
"Why can't someone just build clean, fast tools that work in the browser?"
So I did. In one month, I built ToolKnit — a free, browser-based toolbox with 30+ tools. No uploads. No signups. No ads. Everything runs locally.
What I Built
Here's the full toolkit, organized by category:
📄 PDF Tools
- Compress PDF — Shrink PDFs without losing quality
- Merge PDF — Combine multiple PDFs into one
- PDF to Word / Word to PDF
- PDF to Image / Image to PDF
🖼️ Image Tools
- Compress Image — Reduce file size in-browser
- Image Crop — Crop with custom aspect ratios
- Image Grid Split — Split images for Instagram carousels
- Format converters: JPG↔PNG, JPG↔WebP, PNG↔WebP, WebP→JPG, WebP→PNG
🎬 Video & Audio
- Compress Video — FFmpeg-powered, runs in browser via WASM
- Video to GIF — Make GIFs from any video
- MP3↔WAV converter
⏱️ Utilities
- Stopwatch / Countdown Timer / World Clock
- Character Counter — With social media limits built in
- Extract Text — Pull text from PDF, DOCX, XLSX & 12+ formats
- Keyboard Tester — Test every key on your keyboard
🎲 Fun Stuff
- What to Eat? — A random food picker (yes, really)
- Ask Fate — A Magic 8-Ball for life decisions
- Spinner Wheel — Custom random picker
- Reaction Time Test — How fast are your reflexes?
- Drawing Board — Sketch, doodle & export
The Tech Stack
Nothing fancy. Intentionally simple:
- HTML + Tailwind CSS — Static pages, no framework overhead
- Vanilla JavaScript — No React, no Vue, just plain JS
- FFmpeg.wasm — For video compression and GIF conversion in-browser
- PDF.js + pdf-lib — For PDF manipulation without server uploads
- Canvas API — For image processing (crop, convert, compress)
- Web Workers — Heavy tasks don't block the UI
Every single operation happens in the user's browser. Files never leave the device. This was a non-negotiable design decision from day one.
Lessons Learned
1. Browser APIs are incredibly powerful now
You can compress video, manipulate PDFs, convert image formats, and process audio — all without a server. The gap between "browser tool" and "desktop app" is shrinking fast.
2. SEO is a full-time job
Building the tools was the easy part. Getting people to find them? That's where the real grind is. I spent as much time on meta tags, Schema.org markup, Open Graph images, sitemaps, and blog posts as I did on actual tool development.
3. PageSpeed matters more than you think
I obsessed over Lighthouse scores. Every tool page loads in under 1 second. No heavy frameworks. Lazy-loaded icons. Deferred scripts. The result? Google actually started indexing pages within days.
4. "Simple" tools still have edge cases
A "simple" JPG-to-PNG converter sounds trivial until you deal with EXIF orientation, color profiles, transparency handling, and batch downloads. Every tool had its own rabbit hole.
5. Fun tools drive traffic
My most popular pages? Not the PDF compressor. It's the Reaction Time Test and Keyboard Tester. People share fun tools. They bookmark utility tools.
What's Next
I'm planning to add:
- Background remover (AI-powered, still client-side)
- JSON/CSV formatter
- Color palette generator
- Markdown editor with live preview
If you have ideas for tools you wish existed, I'd love to hear them in the comments.
Try It Out
👉 toolknit.com — 30+ free browser tools, no signup, no uploads, 100% private.
If you find it useful, a bookmark or share would mean the world. I'm a solo developer building this after my 9-to-5, and every bit of support keeps me going. ✨
Built with ☕ and too many late nights by Mr.Dong
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