About KeroTools

KeroTools is a collection of 84 free file tools that run entirely inside your browser. It covers five areas: images (compress, resize, and convert between JPG, PNG, WebP, AVIF, HEIC, SVG, GIF and BMP), PDFs (merge, split, compress, protect, sign, OCR, and conversion to and from Office formats), data files (CSV, Excel and JSON in every direction), text and developer utilities (formatters, encoders, hashes, regex, diff), and design helpers (QR codes, barcodes, colour conversion, contrast checking).

The defining constraint is that nothing you open here is uploaded. When you drop a file onto a KeroTools page, it is read by JavaScript running on your own machine, processed there, and written back out as a download. No copy is sent to a server, because there is no server in the path — only the static page you already loaded.

You do not have to take that on trust. Open your browser developer tools, switch to the Network tab, and run any conversion: there is no upload request, and the tool keeps working if you disconnect from the internet after the page has loaded. That test takes about thirty seconds, and it is the most direct answer to the question people reasonably ask about any free file tool.

This design has real limits, and we would rather state them than hide them. Very large files are bound by your device memory rather than a server, so a 500 MB PDF behaves differently on a phone than on a desktop. A few operations that genuinely require heavy server-side libraries are not offered at all, rather than quietly breaking the privacy promise. And because processing happens on your hardware, an older device will be slower than a fast one.

KeroTools is free and funded by advertising. There is no paid tier, no account system, no per-file quota, and no email address collected before you can download your result. Ads sit in the breaks between content sections, never inside the tool itself, so a misplaced click never costs you a conversion.

The site is available in eight languages — English, Arabic, Turkish, Spanish, French, Portuguese, German and Indonesian — with a genuine right-to-left layout for Arabic rather than a mirrored afterthought. Tool pages are written per tool rather than generated from a template, because a page about converting HEIC on Windows should not read like a page about merging PDFs.

If a tool produces a wrong result, a translation reads awkwardly, or something is simply broken, the contact page reaches us directly. Reports naming a specific file and a specific browser are the ones that lead to fixes.