Does X (Twitter) support WebM files?
an open, web-native format that produces smaller files at a similar quality, popular for embedding on websites
WebM is not listed for X Media Studio uploads.
Media Studio documents MP4 and MOV with H.264 video and AAC audio. Convert WebM for that workflow. The Studio specification explicitly excludes native app, ordinary browser and API uploads, whose current WebM behavior has not been tested here.
Recommended upload: MP4 with H264. WEBM is not the platform's documented upload container; export as MP4 with H264 video for the safest upload.
Convert WebM to MP4 →Source: X Media Studio Library. Media Studio only; not a specification for native app, web or API uploads. Checked 2026-09-12.
Frequently asked
Does X (Twitter) support WebM?
WebM is not listed for X Media Studio uploads. Media Studio documents MP4 and MOV with H.264 video and AAC audio. Convert WebM for that workflow. The Studio specification explicitly excludes native app, ordinary browser and API uploads, whose current WebM behavior has not been tested here.
What format should I convert WebM to for X (Twitter)?
MP4 - a widely supported video container; acceptance also depends on the video and audio codecs inside it. Converting WebM to MP4 runs entirely in your browser with the converter linked below.
How do I check whether my WebM file will upload cleanly to X (Twitter)?
Open the Koldflux File Doctor, drop in the file, and pick X (Twitter). It reads the container, codec, resolution, duration and file size locally and reports pass / warn / fail against the documented X (Twitter) constraints.