I got tired of sending documents to random websites.
Every time I needed to merge a PDF, compress a photo, or rewrite a work email -
I had to hand my files to some server I know nothing about. Most of these sites have ads, want your email, and who knows what happens to your data after.
So I started building something for myself. One tool, then another. Somewhere around tool number 20 I realized I was building an actual product.
ZeroOffice is a single HTML file. Open it in your browser. Your files never leave your device. Close the tab and everything is gone.
What's inside
PDF tools - merge multiple PDFs, split by pages, compress scanned documents, add a watermark, convert to and from images.
Image tools - compress photos for email or web, resize to exact pixels or presets like Instagram or 4K, convert between formats, basic editor with brightness and contrast.
Text and Data - word counter with reading time, compare two texts line by line, view and convert CSV files, build charts from CSV data and export to PNG or Excel.
Converters - live currency rates, unit converter for length and weight and temperature, and more.
AI tools - this part needs a Claude API key. Email rewriter with tone selection, contract analyzer that explains legal text in plain language, invoice generator, document summarizer, business letter writer. New accounts get around 5 dollars in free credits which is enough for several hundred operations with Haiku.
The part I want to be honest about
The AI tools send your text directly from your browser to Anthropic's API. ZeroOffice is not in the middle. Your API key is stored only in localStorage on your own machine. I never see it.
Also - this was built with heavy Claude assistance. My ideas, my decisions, my testing, but Claude wrote most of the code. I'm upfront about this because I think honesty matters more than the impression it might create.
Architecture note
One HTML file. Around 480KB. No npm. No build step. No server. No database. No account.
open index.html
That's the entire setup.
Links
Live: https://darkenamber.github.io/ZeroOffice/
GitHub: https://github.com/DarkenAmber/ZeroOffice
Feedback welcome. Especially if something doesn't work — I test on desktop and Android but I'm sure there are edge cases I've missed.
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