About

Almost every free file converter online works by uploading your file to a server, processing it there, and giving you a link to the result. That model has real consequences: your document sits on someone else’s disk, you wait for two transfers instead of none, and the size of file you can process is capped by what the operator is willing to pay for bandwidth.

Browsers have been able to do this work locally for years. Canvas can decode and re-encode images, WebAssembly can run a full HEIC decoder, and libraries like pdf-lib and pdf.js can read and write PDFs — all client-side. Building on that removes the upload entirely. It is faster, it costs nothing to run per file, and the privacy question stops being a policy promise and becomes a technical fact.

You do not have to take it on trust. Every tool that handles a file shows a live network monitor while it works, which counts the bytes actually transmitted during processing and lists any request it observes. It reads zero because there is nothing to send.

If you would rather verify it independently, open your browser’s developer tools, switch to the Network tab, and run a conversion. You will see the page load, and then nothing while your file is processed. A more decisive test: load a tool page, disconnect from the internet entirely, and convert a file. It still works.

One honest caveat, which is also stated on the tools themselves: the claim is scoped to processing. The site makes ordinary network requests to load itself, and privacy-friendly analytics record that a page was viewed. What never happens is your file being sent anywhere.

toolbook is built and maintained by an independent developer, not a company. There are no investors to satisfy and no data to resell, which is the main reason the no-upload approach is viable here — it is cheap to run precisely because it does not store anything.

Corrections, bug reports, and requests for tools that do not exist yet are all welcome at contact@atoolbook.com. Reports that a tool produced a wrong result are especially useful — a converter that quietly corrupts a file is worse than one that fails loudly, so those get priority.

Some things are left out on purpose rather than not built yet. There are no passport or visa photo presets, because those requirements differ by country and a wrong size means a rejected application. PDF compression is offered as two clearly-labelled modes rather than one button, because a browser genuinely cannot recompress the images inside a PDF while keeping its text selectable, and pretending otherwise would mean silently destroying text layers.

Where a tool has a limitation, the limitation is written on the page. That is a more useful thing to offer than a claim that everything works perfectly.