Redact (black out) the parts you don't want to share before posting or sending an invoice, contract, ID document, chat window, or screenshot — names, addresses, phone and account numbers, ID numbers, faces, or confidential figures. Drop an image (or paste it with Ctrl/Cmd+V) and drag a box over anything you want to hide; that area is covered with a solid black box. Choose how to hide it — Black box, Blur, or Pixelate — and add as many areas as you need. For genuinely sensitive data a black box is recommended: blur and pixelate keep some of the original look and, at low strength, the content can sometimes be partially read or reversed (the tool shows this warning when you pick blur or pixelate). Each area is layered non-destructively over the original and is only baked in when you download, so you can freely add and undo (Undo box / Clear all). Everything — loading, compositing, and exporting — happens inside your browser (canvas); the image is never uploaded, stored, or sent to a server, so it's safe for confidential documents or captures with private data. The output is a PNG, and black-box areas are painted fully opaque, so the original pixels are not present in the exported image. If you only want to auto-detect and blur faces in bulk, the Mosaic tool's face detection is handy; this tool focuses on quickly hiding any rectangular area.