Add Watermark Online — Free, Fast, Private

How Add Watermark to Video Works

A video watermark works by rendering text as a fixed overlay on top of every frame in the sequence, then re-encoding the frames back into a video file. This tool decodes your uploaded video, draws each frame to an HTML5 Canvas, composites your chosen text at a set position with the color and opacity you picked, and captures the output through the MediaRecorder API. Unlike a caption or subtitle track, which is a separate data layer a player can toggle, the watermark becomes part of the actual pixel data of the video — anyone viewing, screen-recording, or re-uploading the clip sees it, because it's no longer optional metadata, it's baked into the image itself.

This matters most for people distributing footage before it's finished or fully licensed: agencies sending rough cuts to clients who shouldn't publish an unapproved version, stock footage sellers previewing clips before purchase, and creators sharing draft edits for feedback without wanting them reposted as final. A text watermark is lightweight to apply and immediately visible, which makes casual misuse obvious and discourages it — even though a determined person with editing software could eventually crop or paint over a corner watermark. It's a deterrent and an ownership mark, not cryptographic protection.

Text watermarking is closely related to a couple of other tools in this category. If what you actually need to overlay is a brand mark or icon rather than text, the Add Logo tool applies the same frame-by-frame compositing technique to an image file instead. Both tools share the same underlying rendering pipeline — decode, draw, composite, re-encode — just with different overlay content.

A practical note on output: MediaRecorder's supported container format depends on the browser, so Chrome and Edge typically produce WebM while Safari produces MP4. Both play back fine almost everywhere, but if a downstream platform specifically requires one format, you may need to convert afterward with a desktop tool. Because watermarking re-encodes the whole video, very long or high-resolution clips take proportionally longer to process — trimming to just the segment you need to protect before watermarking keeps render times reasonable.