The Moment I Snapped
A few months back I needed to merge three PDFs into one. Small job. Should take ten seconds.
I opened the first result on Google. It uploaded my files, slapped a watermark on the output, and asked for $9.99/month to remove it. The second site asked for my email before letting me download. The third one ate one of the pages.
I closed the laptop and thought: this is a solved problem. The browser already has everything we need. So why is everyone selling it back to us?
A weekend later I had a working PDF merger. Then a splitter. Then a compressor. Now there are seven tools on aayushali.com/tools, all free, all running in your browser, none of them ever touching a server.
This post is about why that matters and how it works.
Your PDFs Never Leave Your Computer
Every tool on the site processes files locally. That's not marketing. Open the network tab in DevTools while you use one — you'll see the file download for the final result, but nothing uploads. There's nothing to upload to. There's no backend.
Here's the rough flow when you, say, compress a PDF:
[Your file]
│
▼
[Browser reads it into memory]
│
▼
[PDF-lib processes the bytes]
│
▼
[Browser triggers download]
That's it. Your tax return, your contract, your medical scan — they exist on your machine and nowhere else.
I added a privacy banner on every tool page just to make it obvious. People are conditioned to expect surveillance, and "free" usually means "you're the product." Being explicit about it builds trust faster than any pitch.
What's Actually In The Toolbox
Right now there are seven tools live:
| Tool | What it does | Best for |
|---|---|---|
| PDF Editor | Add text, draw, sign, fill forms | Signing contracts |
| Merge PDF | Combine multiple PDFs into one | Combining receipts |
| Split PDF | Extract specific pages | Pulling one page out of a long report |
| Compress PDF | Reduce file size | Email attachments under 5MB |
| Rotate PDF | Fix sideways pages | Scanned documents |
| PDF to Image | Convert pages to PNG/JPG | Sharing a single page on Slack |
| Image to PDF | Bundle images into a PDF | Submitting photo IDs |
There's also an image resizer that's not strictly PDF but ended up there because the same upload/process/download pattern works for it.
The Tech Stack, Briefly
If you're a developer, here's what's doing the heavy lifting:
- PDF-lib for creating and modifying PDFs (merge, split, rotate, form fill)
- PDF.js for rendering pages to canvas (preview, page-to-image)
- Fabric.js for the annotation layer in the editor
- Signature Pad for capturing hand-drawn signatures
All of it runs client-side. The Nuxt app serves static HTML, JS, and CSS. The "server" is a glorified file server.
The trickiest part wasn't any single library — it was getting the editor to feel right. PDF coordinates are inverted (origin bottom-left), Fabric canvas coordinates are normal (origin top-left), and the on-screen render scale is whatever fits your viewport. Reconciling those three coordinate systems took an embarrassing number of evenings.
I wrote about that in detail in the PDF editor tech stack post.
What You Give Up
I want to be honest about the tradeoffs.
Speed on huge files. A 500-page PDF will make your browser sweat. PDF-lib reads the whole thing into memory. On modern machines this is fine for anything reasonable, but if you're processing million-page legal discovery dumps, you want a server.
OCR. I haven't built optical character recognition yet. Scanned PDFs without a text layer come out as images. There are libraries that do OCR in the browser (Tesseract.js) and it's on my list.
Batch operations. You can merge multiple files at once, but you can't queue 50 separate jobs. That's a workflow problem more than a technical one.
For 90% of what people actually need PDFs for — sign this, send that, shrink this, rotate that — browser tools are honestly faster than desktop apps. You don't wait for software to launch. You drag, click, download.
Why It's Free
Two reasons.
First, I built these tools because I needed them. Keeping them free costs me nothing extra — they're static files on a server I already pay for. No usage limits to enforce, no accounts to manage, no payment integration to maintain.
Second, I'm a developer for hire. The tools are a calling card. If you find them useful and you also happen to need someone who can ship full-stack apps that respect users, you know where to find me.
That's the whole pitch.
Try Them
If you've got a PDF that needs something done to it right now, here's the tools page. Drag your file in, do the thing, download the result. No signup. No email. No upload.
If you find a bug or have a tool request, I'm reachable at [email protected].
And if you're a developer thinking about building something similar — do it. The browser is more capable than most of us give it credit for, and there's a whole class of "freemium SaaS" that frankly shouldn't exist. The user's machine is right there.