A practical layer against document reuse
Watermarkit makes purpose and limits visible while being honest about what a watermark can and cannot do.
What the application does
Repeated diagonal text covers the full page, including portraits and key fields. Optional footer, border, local reference, and QR marker make the intended recipient and purpose easy to see.
Flattened exports
Image pixels are decoded into a canvas, the watermark is drawn directly into those pixels, and a new file is encoded. Every PDF page is first rasterized, watermarked, and embedded as a full-page image in a new PDF. There is no removable text layer or annotation.
Threat model
This design helps discourage casual reuse, cropping, and simple layer deletion. It does not protect against malware on the device, screenshots, physical camera capture, skilled image editing, coercion, or a recipient who already possesses the original.
Honest limitation
No protection method can guarantee that a document cannot be altered. A flattened, dense watermark is tamper-resistant, not tamper-proof, and does not verify whether the original identity document is genuine.
Browser safeguards
Files are limited by count, size, page count, type, and signature. SVG and HEIC are rejected. Large canvases are blocked before they exceed a conservative memory estimate. Security headers restrict content sources, referrers, MIME sniffing, and unnecessary browser permissions.