Why we built it
Almost every "free online tool" site works the same way: you drop a file, they upload it, they process it on their server, they send you the result. Which is fine for a picture of your dog. It's a problem for anything you'd rather not have sitting on somebody else's hard drive for the next several years — a redacted contract, a medical scan, a therapy transcript, a founder's unreleased financials, an unreleased draft.
Modern browsers can do the processing themselves now. WebAssembly can runpdf-lib, FFmpeg, image encoders, ONNX models for background removal, all at speeds close to native. Your CPU has plenty of horsepower. Your GPU is idle most of the time. There's no reason your files need to leave your machine to get a PDF split or a JPG converted to WebP.
So we built a site that assumes the browser is the server.
How it works
When you open a tool page, your browser downloads a small React app and (for a few tools) a WebAssembly library. Your file, when you pick one, is read directly by the browser using the File API. The work happens in a Web Worker or on the main thread, entirely on your machine. The result gets written back to your disk by the browser.
You can verify this at any moment: open the Network tab in your browser's dev tools before running a tool. You will see the libraries load. You will not see your file bytes go anywhere.
What's here today
- PDF tools — merge, split, rotate, extract text and images, add page numbers, watermark. Built on
pdf-lib. - Image tools — resize, compress (with specific byte targets), convert between formats, crop, rotate, flip. Built on the browser's native Canvas + WebGL.
- Calculators — age, BMI, and everything you can build from those.
- Text utilities — JSON formatter, base64, hash, JWT decoder, URL and HTML entity codecs, case converter, word counter, Lorem Ipsum, QR generator.
- Converters — CSV ↔ Excel ↔ JSON ↔ XML for structured data.
We're adding more every week. See the full list at /tools.
What's not here yet
Some tools genuinely need a server — large-language-model text generation, big GPU rendering jobs, live video transcoding. Those pages are marked Coming Soon with an honest explanation. We're not going to fake them by shipping your file to some third-party API and calling it a browser tool.
How we pay for it
The site is ad-supported (Google AdSense). We don't sell your data — we don't have data to sell. We don't run affiliate spam. Ads pay the hosting bill. Ad blockers are welcome. If you'd prefer to help another way, get in touch — contact.
The stack, briefly
Toolspace is built on Next.js 16, React 19, TypeScript, and Tailwind. The heavy lifting for actual tools uses pdf-lib, FFmpeg.wasm, SheetJS, jszip, qrcode, and @imgly/background-removal. All open-source, all runnable in your browser.
Read more
The blog has long-form pieces on why on-device AI matters, how to verify a tool actually runs in your browser, and how to invoke Toolspace from ChatGPT / Claude / Perplexity.
Get in touch
Anything you want to build with us, break for us, or ask us: [email protected]. Or use our contact page.