WhatsApp has a hard file size limit, so the resolution you pick matters more here than anywhere else.
Save a video from X in a form WhatsApp will accept. WhatsApp has a hard file size limit, so the resolution you pick matters more here than anywhere else. The download is a plain MP4 copied straight from X, with no watermark added and nothing re-encoded, which is exactly what WhatsApp wants as an input. Below: the requirements that actually matter, which resolution to pick, and the mistakes that cause an upload to be rejected or look soft.
WhatsApp caps ordinary video at 16 MB per message, which works out at about one minute at 1080p or two to three minutes at 720p. Status updates are limited to 30 seconds and are split automatically beyond that.
The download here is an ordinary MP4 with H.264 video and AAC audio, which is the format WhatsApp is built around. There is no conversion step to get wrong and no container to fix.
This is the one case where the highest resolution is often the wrong choice. Take 720p for anything over a minute, and 480p for long clips: WhatsApp will compress a file that exceeds the limit anyway, and its own compression is worse than simply starting smaller.
As a general rule, take the highest resolution the post offers. WhatsApp will compress whatever you give it, and starting from a better source means the compression has more to work with. Handing it a 480p file to save time produces a visibly worse result than handing it 1080p, because every stage of compression after that is working from less.
WhatsApp does not enforce an aspect ratio and plays landscape, square and vertical alike. Nothing needs cropping unless you want it cropped.
This is the single most common reason a re-shared clip looks wrong. Most X videos are landscape or square, because that is how they were filmed, and forcing one into a vertical frame either crops the sides off or leaves bars above and below. Neither is fixed by the download; both are fixed in whatever you crop with before uploading.
X does not brand the video files it serves, and nothing is added here either. What you download is what was published.
If you have seen watermarked downloads before, they came from a tool that added its own branding to advertise itself, not from X. That is worth avoiding for WhatsApp specifically: a visible third-party watermark reads as reposted content, which is the kind of thing recommendation systems quietly deprioritise.
Attach the file from Downloads using the paperclip, then Document to send it uncompressed, or Gallery to let WhatsApp compress it. Sending as a document preserves quality but the recipient has to download it before it will play.
On a phone, the file lands in your Downloads folder or the Files app, and every app that accepts video can reach it from there. On a computer it goes to Downloads and can be dragged straight in. No import, sync or library step is needed in either case.
Reposting is where copyright actually bites. The person who filmed or posted the video owns it, and saving a copy does not change that, whatever platform it ends up on. Most platforms, WhatsApp included, will remove reposted content on a rights-holder complaint and may penalise the account that posted it.
Credit is not a licence, but asking is usually enough: many people are happy to have a clip re-shared if they are asked first. Saving a clip for yourself, or re-sharing your own posts across platforms, raises none of this.
Open the post on X, tap or click Share, then Copy link.
Drop the link into the field at the top of this page.
Take the highest resolution offered, then upload it to WhatsApp as you normally would.