About Kalio

Kalio is a collection of 37 everyday tools - calculators, converters, generators and file utilities - that all share one property: they do their work on your device rather than on ours.

Why this exists

Search for “merge PDF” and you will find dozens of services. Almost every one asks you to upload your document to a server you know nothing about, and offers a privacy policy in exchange. Some delete files after an hour. Some do not say. All of them have, at minimum, held a copy of your contract, your bank statement or your medical record on someone else’s machine.

For a great many tasks that upload is simply unnecessary. Browsers have been able to read files, decode images, render PDFs and perform cryptography locally for years. The work can happen where the file already is.

So that is what these tools do. Not as a feature, but as the whole design: there is no server that receives your data, which means there is no retention policy to trust, no breach that could expose your files, and no limit on file size beyond what your own device can handle.

What we will not do

• No sign-up. Not for the good features, not for batch processing, not for anything.
• No watermarks and no deliberately degraded free tier.
• No daily limits. There is no server cost that scales with your usage, because there is no server doing the work.
• No selling data. We do not have any to sell.

How it stays free

Advertising, eventually. The site does not carry ads today, and when it does they will sit outside the tool area in space already reserved in the layout - so adding them will not shift content or slow the page down. That is the whole business model. There is no premium tier waiting behind a wall.

How it is built

Static HTML generated by Astro, served from Cloudflare’s edge network. Interactive tools are small Preact islands, so a page ships almost no JavaScript until you actually use the tool on it. Heavier libraries - pdf-lib, pdf.js - are loaded only at the moment you drop a file in, rather than on page load.

The tools rely on open-source work by many people, including pdf-lib, pdf.js and qrcode-generator. Cryptographic operations use the browser’s own Web Crypto API rather than a reimplementation.

Honest limitations

Client-side processing is not free of trade-offs, and it is worth stating them plainly:

• Memory is the ceiling. Very large files can exhaust what a browser tab is allowed to allocate, particularly on phones.
• Browsers cannot decode everything. HEIC photos from an iPhone and camera RAW files need software we cannot run in a tab.
• JavaScript is required for the tools themselves, since the computation happens locally. The explanations and reference tables work without it.
• Some jobs genuinely need a server. Where that is true, we say so rather than shipping a worse version of it.

Who builds it

Kalio is built and operated by PT RHP Cipta Digital. If a tool gives you a wrong answer, or you need one that is not here, we would genuinely like to hear about it - write to hello@example.com or use the contact page.