You filmed one video. Uploading it three times, rewriting the caption three times and picking a cover three times is the part that eats your evening. Here's how to publish once and have it land everywhere, without the post looking copy-pasted.
Why post the same video everywhere
Short vertical video works on Instagram Reels, TikTok and YouTube Shorts in almost the same format: 9:16, under a minute or so, hook in the first two seconds. Each platform's audience is mostly separate, so the same video gets a second and third shot at finding viewers for almost no extra work.
What shouldn't be identical is the text around it. Each platform reads it differently:
| Platform | What the text does | What works |
|---|---|---|
| Instagram Reels | Caption under the video, hashtags help discovery a little | A short hook line, a sentence of context, 3–5 specific hashtags |
| TikTok | Caption is searchable and shows over the video | Keywords people would actually search, one clear line |
| YouTube Shorts | Title carries most of the weight, description is secondary | A searchable title under 100 characters, a short description |
Before you post: export once, correctly
- Format: MP4 or MOV, vertical 1080×1920.
- Keep text away from the edges. Each app overlays buttons and captions on the right side and bottom. Keep important on-screen text in the middle area.
- Burn in captions if you use them. Most people watch muted. If you need word-by-word captions, Captions to Titles turns your speech into styled, word-synced titles you can export as a Final Cut Pro file, a transparent overlay, or an MP4 with captions burned in.
- No watermarks. Don't upload a video downloaded from one app (with its logo) to another. Export the clean file from your editor.
Step by step in PostKit
- Connect your accounts once. In the Publisher, connect Instagram, TikTok, YouTube (and a Facebook Page if you use one). You only pick from platforms you've connected. For YouTube, sign in with the Google account that owns the channel; if your channel is a Brand Account, choose that one when Google asks.
- Choose "Short-form video" and upload your file.
- Write the caption per platform. Each platform gets its own tab. Write the Instagram caption, then switch to TikTok and tighten it around search keywords, then give YouTube a proper title (up to 100 characters) and description. PostKit adds the #Shorts tag for YouTube for you.
- Pick the cover. On Instagram you can upload a cover image or pick a frame; on TikTok you pick a frame; on YouTube you can upload a thumbnail. Choose a frame where your face and the on-screen hook are both clear.
- Post now or schedule. Hit post to send it everywhere at once, or schedule each platform for later. If a post fails on one platform, you can retry just that one.
Picking a posting time
There's no universal best time. A better rule: post when your audience is awake and scrolling, and be consistent. Check each app's audience insights for the hours your followers are most active, then schedule there. Posting at the same few times every week also makes it easier to compare which videos did well.
Carousels too
The same flow works for photo posts. Choose Carousel, add up to 10 images, and it goes out as an Instagram carousel, a TikTok photo post and a Facebook multi-photo post. YouTube is skipped automatically because it doesn't support carousels.
A quick checklist
- Vertical MP4/MOV, no watermark, text inside the safe area
- Hook in the first two seconds
- Instagram caption with a hook line and a few specific hashtags
- TikTok caption written around search keywords
- YouTube title that someone would actually type into search
- Cover frame picked for each platform
- Your link in bio points somewhere useful (a product, a booking or your email list)
That last one matters more than it looks. Posting everywhere sends people to your profile; your link in bio is what turns that attention into subscribers or sales. See how to sell digital products from your link in bio.