Most file-conversion workflows start with a trade-off that is easy to miss: Choose a file from your device. Upload it to a third-party server. Wait for processing. Download a new file. Trust that the original and the result are handled exactly as promised. That model is convenient, but it is not the only option. For a growing set of formats, a modern browser can read, transform, and export files directly on the user's device. The result is a different kind of tool: no upload qu...