Connect X to YouTube

Before you start

• An X account. Any account you can sign in to works.
• A YouTube channel on the Google account you sign in with.
• A Post Once account. The free plan includes 10 reposts, with no card needed.

How to connect X to YouTube

1. Create a free account at app.postonce.com. After two short intro screens, Post Once asks where you post.

2. Under Where do you post first?, pick X and press Continue.

   

3. Under Where else should it land?, pick YouTube. Add any other apps, or a backup, then press Continue.

4. On Connect your accounts., press Connect on the X row. Sign in on X’s page and authorize Post Once.

   

5. Press Connect on the YouTube row. Sign in with the Google account that owns your channel and allow access.

6. When both rows say Connected, press Go to dashboard.

From then on, keep posting on X as usual. Post Once checks it about every minute and reposts each new post to YouTube.

Already using Post Once?

If X is already the source of your bridge, open Bridge and press Connect next to YouTube in the Destinations card, or press Add destination on the dashboard.

If your bridge reads from another account, add a second bridge with X as its source from the bridge switcher. Free and Solo include 1 bridge, Studio 3 and Agency as many as you need. See bridges.

What each X post becomes on YouTube

On X	On YouTube
A video up to 3 minutes, vertical or square (the first one, if a post has several)	A Short. YouTube decides this from the video, so vertical or square videos up to 3 minutes show as Shorts.
A video over 3 minutes, or a landscape one	A regular YouTube video, up to 2 hours and 4K.
A photo	Skipped, with “YouTube does not accept photos”.
A post with several photos	Skipped, with “YouTube does not accept photos”.
A text post	Skipped. YouTube only takes videos.

A skipped post shows the reason on your dashboard and still goes to your other destinations. See long videos for how Post Once tells short from long.

How your caption carries over

The post text goes with each repost, and each t.co link is turned back into the full address. Replies, reposts of other people’s posts, quotes with no video or photo, polls and GIFs are not reposted.

YouTube fills in each upload like this:

YouTube field	What Post Once puts there
Title	The first line of the caption, up to 100 characters. With no caption it names the source, for example “X video”.
Description	The full caption, up to 5,000 characters.
Tags	Every hashtag in the caption, without the #. Each tag up to 30 characters, 500 characters in all.
Visibility	Public.
Made for kids	No.

Write the first line of your caption like a title and your YouTube uploads read well too.

Choose what goes to YouTube

On the Bridge page, the YouTube row has two settings.

• What to post has one switch here, Videos, since videos are all that go from X to YouTube. Turning it off pauses YouTube.
• Rewrite caption changes the caption for YouTube only: Remove comment, DM and link in bio prompts, Remove hashtags and mentions, Rewrite with AI to suit YouTube, and Add your own text at the start or end. Each one is off until you turn it on.

Check that it works

Post something on X as usual. Within a minute or two it shows up under Your posts on the dashboard, then goes to YouTube. Each post shows where it went, what was skipped and why.

If a repost fails, Post Once tries again up to 5 times over about half an hour. If it still fails, you get an email, and Retry sends it again to just the accounts it missed. See a post did not repost.

Only posts published after you connect are reposted on their own. Older ones are listed in Your posts, where you can send any of them by hand.