What is safedocument?

SafeDocument is a single HTML file, with no dependencies, no build step, no server, and no network access, that adds a destructive watermark to photos of ID cards, passports, or invoices before you send them somewhere like a hotel or landlord. The README explains the problem it targets: once you hand over a plain photo of your ID for one purpose, that same file can be reused for anything else, since nothing ties it to why it was shared. Instead of overlaying a watermark on top of the image, the tool replaces the actual pixels underneath with the stated purpose, printed repeatedly across the document, and destroys the original color data in a way that cannot be undone. The README stresses that this is the real protection: removing the mark does not recover the original document, it means fabricating a new one, and a fabricated ID is a forged document with legal consequences for whoever uses it. The tool also lets you black out fields the recipient does not need, such as a support number or signature, before adding the mark. Using it means opening the HTML file directly in a browser, with no installation required, and the README specifically recommends turning off WiFi first since the app works identically offline. Workflow is drag in a document, redact unneeded fields, type a specific purpose such as a named hotel reservation with exact dates, then generate and download the result. Privacy claims are enforced by a Content Security Policy declared in the page itself that blocks all network requests, images, and outside resources, rather than relying only on a written promise in the README. The README is explicit about what SafeDocument is not: it is not encryption, since the recipient still reads your personal data in plain sight, it is not anonymization, since your name and ID number remain visible, and it is not a technical guarantee against someone simply photographing the screen or retyping the data by hand. It is offered as a semantic and legal deterrent built around a single, auditable, roughly 860-line file, released under the CC0 1.0 public domain license. The full README is longer than what was shown.