Will this stop leaks?
No. Nothing can stop someone from forwarding a file. But every copy quietly carries the name of the buyer you sold it to. When you find a leak, you know who did it and can talk to that buyer or report the post. The visible line “Licensed to …” alone already stops many people.
Can I mark pictures, not only PDF?
Yes: JPG, PNG and WEBP — illustrations, prints, stickers, photos. The same hidden pattern goes into the picture, and the copy is saved in the same format. On very dark pictures the pattern is weak — the visible line helps there.
Where do my files go?
Nowhere. Everything happens in your browser, on your device. The page is technically forbidden from sending data to the internet. There is no server that could receive your files.
What if someone takes a screenshot or a photo of the screen?
The main hidden mark is an almost invisible pattern across the whole page. It usually survives screenshots, Telegram compression, cropping, rotation and phone photos. The picture needs to be reasonably sharp: a blurry photo with strong glare may not be readable.
Is the mark visible? Will it spoil my chart?
At the default “medium” level it is a barely noticeable warm paper tint. Colours, lines and symbols stay sharp. For printing there is a “high” level with a more visible texture. Look at your copy before sending it.
What if the buyer prints and scans the file?
A colour scan usually keeps the mark. Scanner apps that turn pages into pure black and white erase the pattern. Then the visible line with the buyer’s name still helps, unless it was cut off.
Where is my buyer list stored?
Only in this browser on this device. If you clear the browser or switch computers, it is gone. So once a week press “Save a backup” — you get a file you can load back at any time.
Is it free?
Yes. If the tool helped you, you can buy the author a coffee — it keeps the project going.
Is this legal protection?
No, and it is not legal advice. The tool helps you show that a file is your licensed copy and fills in a complaint template. The platform decides what to remove.
