Short vertical video goes to several networks, and the file is usually the same. What changes is the caption, the rules around it and what each network does with the upload.
Upload the video once in the composer and select the networks. The same file is attached for every network that takes video, and you write the caption in the master draft, with a different version per network when you need one.
The composer accepts MP4, MOV (QuickTime) and WebM files. After the upload it shows the video's length, its pixel size and its file size on the thumbnail so you can check them.
A post holds one video. A video cannot be mixed with images in the same post, so if you want a photo post as well, make it a separate post.
Some networks cannot publish a text-only post. TikTok and YouTube need a video, and Instagram needs an image or a video. The composer shows a "needs" hint for each selected network while you edit. It is a warning, not a guarantee, so the network can still reject a post it does not like.
Captions are held to each network's limit: TikTok 2200 characters, Instagram 2200 and YouTube 5000. TikTok and Instagram are close, so one caption usually fits both. YouTube has more room.
If you share one master caption, the composer holds it to the strictest limit among the networks that still use it. A network with its own tab is checked against its own limit only. Hashtags count as characters.
fanout does not check a video's length, resolution, aspect ratio or file size against a network's rules. It shows you the numbers, and the network decides whether to accept the file. These requirements also change, so look at each network's current specs before you rely on them.
General advice that holds for short vertical video: shoot in portrait, keep the important part away from the screen edges where the app's own buttons and text sit, and write a caption that makes sense without audio.
The composer has no setting that chooses a format on the network, such as a Reel or a feed post on Instagram, or a Short or a regular video on YouTube. How the network classifies the upload is up to the network. After your first post, open it on each network and confirm it appeared the way you wanted.
Pick a date and time instead of publishing now and the video goes out at that moment. Upload and check the file before you schedule. A missing or wrong file is the usual reason a scheduled video goes wrong.
A different time for one network means a separate post for that network.
Analytics in fanout cover X (Twitter), Instagram, TikTok, YouTube, Threads, Facebook and Pinterest. The per-post view adds video statistics such as watch time and completion where the network reports them. Networks not in that list show no analytics yet.
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Yes. Upload the video once, select the networks and publish or schedule. Each network can have its own caption.
The composer accepts MP4, MOV and WebM files. Whether a network accepts a given file is up to the network.
No. The composer shows the length, size and resolution of your upload, but it does not compare them with a network's rules.
No. A post holds one video and a video cannot be mixed with images.
Social media character limits for every network · Schedule social media posts across networks · How to cross-post to multiple social networks · TikTok scheduler · Instagram scheduler · YouTube scheduler
Last updated 2026-10-25.