I build ToolsByUs, a suite of 135 free browser tools for JSON, PDF, images, video, audio, and text. There is no account, and no server endpoint waiting to receive your file. That last part is the whole design decision — and it shapes everything else about how the site is built.

The rule is narrow, on purpose: your file's contents never leave the browser. The tool runs in your tab, on your machine. That is different from the usual promise of "we delete your files after processing." There is nothing to delete, because the contents were never sent.

A worked example, with a tool you can try in seconds: the JSON Formatter.…