rosuH / EasyWatermark

🔒 🖼 Securely, easily add a watermark to your sensitive photos. 安全、简单地为你的敏感照片添加水印，防止被人泄露、利用

zhensherlock / watermark-js-plus

Lightweight, framework-agnostic browser watermark library with text, image, rich-text and blind watermarks, decoding, grid layouts, and tamper protection.

tooladda-online / pdf-watermark

Add Watermark to PDF — Add text, image, or logo watermarks to any PDF with live preview, diagonal tiling, opacity control, and page selection. Everything runs in your browser — no upload, no registration, original text stays selectable. Free on ToolAdda.online.