Limits
Pro uploads and batch ZIP
The website stays free. A hand-issued key raises the file cap so a 512 MB machine is not an open hopper for 50 MB dumps from every IP.
Free (no key)
One image at a time, up to 20 MB. Compress, convert, resize, flat cutout, palette. Ads may appear.
Pro (UNDERKB_PRO_KEYS)
Send X-Api-Key or Authorization: Bearer, or open the site with ?key= and we store it in this browser. Then: 50 MB per file, and on Compress a ZIP of up to 20 images (processed one after another).
POST /api/compress-batch X-Api-Key: YOUR_KEY # multipart fields: file (repeat), target_kb, format
No card form on this page. We issue keys by hand.
Request a key on GitHub Open compressor
A key is not permission to ignore copyright. See Terms.