WebVTT is the W3C standard subtitle format for HTML5 video, used by every browser when you set `<track src="captions.vtt">` on a `<video>` element. Differs from SRT mainly in syntax (`.` decimal in timestamps, `WEBVTT` header, no cue numbers required) plus optional cue settings for position and style. YouTube, Vimeo, and modern OTT platforms all accept WebVTT.
How to open
Any text editor. Browsers render WebVTT inline when attached to a video element. Subtitle Edit and other tools convert between WebVTT and SRT.