Acceptable: Convert Files as You Upload by Nicolas Piplard

A site takes only JPG and PNG, and your photo is a HEIC. A form wants an Excel workbook, and your contacts are a CSV. Pick the file or drop it, as you always do: Acceptable sees that the site expects another format, converts the file in your browser, and hands the site the converted one. A notice at the bottom of the page says what became what, with a button to undo it.

What it converts

• Pictures: a WebP saved from a page becomes the PNG a site takes
• Tables: a JSON export becomes a CSV, or an Excel workbook
• Archives: a ZIP becomes a TAR, and back
• Videos: a MOV from a phone becomes an MP4, its pictures and sound moved as they were
• Audio: a WAV recording becomes an MP3

Every format it reads and writes: https://acceptable.nicolas.nz/#formats

When a site writes the heaviest file it takes, as "Max. file size: 1 MB", and your picture weighs more, Acceptable makes it light enough before the site sees it, when it can: at the best quality that fits, as JPG or AVIF where the site takes one, and smaller only when that is not enough. The notice says the limit it read, with Undo, or why your picture stayed as it was. It reads that limit in English, French and four other languages, and makes no picture lighter where a site writes none.

A file only becomes a format of its own kind: a picture never becomes a table. When the site takes several formats your file could become, Acceptable asks you which. When the file picker of a site lists only some formats, Acceptable adds the ones it can convert, so that you can pick your file. When a conversion keeps only part of your file, a frame of an animation or a sheet of a workbook, or when the format it becomes throws detail away, the notice says so.

Acceptable leaves a file larger than 25 MB as it is, or than 50 MB for a picture a site asks to be lighter, unless you raise that limit in its options, up to 250 MB.

Your files stay on your device

Every conversion runs in your browser. Acceptable has no server, makes no network request of its own and collects nothing: no analytics, no account, no identifier. It keeps on your device the sites you turned it off for, the largest file you let it convert, and a history of its last 100 conversions: which format became which, on which site, and when. Never the file, and never its name. You can clear that history from the popup.

Why it runs on every site

A file input or a drop zone can be on any page, so Acceptable asks to run on every site, and your browser warns that it can "Access your data for all websites". On a page, Acceptable looks only at file inputs and drop zones: which formats they accept, the files you give them, and the words near the one you give a file to, where a site writes the heaviest file it takes. It uses nothing else of the page, and keeps none of those words. You can turn it off for any site from its popup.

Private windows

Acceptable does nothing in private windows, and cannot be let into them.

License

Acceptable is free software, under the MIT License that comes with it in its NOTICE.txt: you may copy it, change it and take it apart. It holds libheif and libde265, under the GNU Lesser General Public License, and LAME, under the GNU Library General Public License. Their texts come with it too, with the license of every other library it holds.

Privacy policy