Quick definition
WebM is a web-focused video format designed for efficient browser playback and online delivery.
Best use cases
Web video embeds, lightweight browser playback, HTML5 video, and open web publishing workflows.
What to watch out for
Some editing apps, older devices, and upload portals still expect MP4 instead of WebM.
Related converters
Conversion tip
Keep the original file, create a converted copy, then compare file size, quality, and compatibility before deleting or uploading the result.