We all have that moment. You need to merge two PDF contracts or compress a video file, and you search on Google. You find a tool, upload your file, and then... you wait.
And then you wonder: "Wait, did I just upload my tax return to a random server in a country I can't pronounce?"
That paranoia is exactly why I built DuneTools.
I wanted to challenge the status quo of heavy, server-dependent web apps. My goal was simple: build a suite of tools (PDF, Video, Image) that runs 100% in the browser. No uploads. No privacy risks. Just pure JavaScript.
Here is how I built it (and why I ditched React for this one).
1. The Architecture: Client-Side is King 👑
Most PDF tools work like this:
User -> Upload -> Server processes (Python/PHP) -> Download
DuneTools works like this:
User -> Browser (WASM + JS) processes -> Done
By using libraries like pdf-lib and WebAssembly wrappers for FFMPEG, modern browsers are powerful enough to handle heavy media editing. This has two massive benefits:
- Privacy: The file never leaves the user's device.
- Cost: My server costs are flat. Whether I have 10 users or 10,000, I don't pay for CPU processing time.
2. Why Vanilla JS? (No React, No Vue) 🍦
I know, I know. It's 2025. Why aren't you using Next.js?
For a tool like this, performance is the feature. I didn't want to ship 200KB of hydration scripts just to render a "Merge PDF" button.
My "Hybrid" Build Workflow
Instead of a heavy JS framework, I use Python as a static site generator:
- I write my logic in plain Vanilla JS.
- I use Python + Jinja2 templates to generate the HTML pages for each tool (SEO is crucial here).
- The Python script compiles everything into a static folder ready for deployment.
The result?
- Lighthouse Score: 100/100 🟢
- Load Time: Instant.
3. The Deployment: Vercel (Zero Config) ▲
Since this is a client-side app with no backend database, I didn't want to manage servers, SSH keys, or Docker containers.
I chose Vercel for deployment. It fits perfectly with my "lazy developer" philosophy:
- Git Integration: I push my generated static files to GitHub, and Vercel detects the change and deploys automatically.
- Global CDN: My static assets (JS/WASM) are cached on the edge, making the tool load instantly from anywhere in the world.
- Cost: Free. Since I'm not using Serverless Functions for processing (remember, it's all client-side), I stay comfortably within the free tier limits.
It’s the ultimate "set it and forget it" setup.
4. The Result: DuneTools 🏜️
The project is now live. It includes:
- PDF Tools: Merge, Split, Compress.
- Video: Converter, GIF maker.
- Images: Compression, resizing.
It’s fast, it’s free, and most importantly, it’s private.
I'd love for you to roast my code or give me feedback on the UX.
👉 Try it here: DuneTools.com
(P.S. If you are an Indie Hacker looking for a privacy-first alternative to iLovePDF, I built this for you!)
Top comments (3)
"Thanks for reading! 👋 I'm the creator, hanging around to answer any questions about the tech stack (Vanilla JS + WASM + Vercel) or the privacy architecture. Let me know what you think!"
Please, chare your repo
"Hey! 👋 Thanks for the interest.
Since this is a bootstrapped project that I plan to maintain long-term, I'm keeping the full website source private for now.
However, I believe in transparency! I’ve just created a dedicated repository sharing the core Vanilla JS implementation (the merge_core.js logic) to demonstrate exactly how the client-side processing works without servers.
You can check the code here: 👉 github.com/DuneTools/dune-client-s...
Let me know if that helps explain the architecture!"