01
Why one caption doesn't fit every platform
Each platform reads text differently. Threads rejects a post over 500 characters outright, it doesn't cut it, the post fails. YouTube limits a description to 5,000 bytes, not characters, so accented letters and emoji count double or more. And YouTube ignores every hashtag on a video that has more than 60, while only three of them show above the title.
The preview applies those rules the same way Uplonic does when it publishes: the long text goes to platforms with a description field, the short caption to the feeds where only the first line shows, and the hashtag list is cut from the end, so your most specific tags survive.
02
Hashtag caps per platform
YouTube: 15, our own cap: YouTube ignores all hashtags only above 60, but it shows just three above the title, so a long list mostly clutters the description. Instagram: 30, Instagram's documented maximum. TikTok: 5, because more tags dilute rather than reach. Threads: 8, to leave room inside the 500-character limit. Facebook: 10. Pinterest: 5, inside a 500-character description. Snapchat: none, since its 160-character caption has no room for them.
These caps are Uplonic's publishing rules, built on each platform's documentation where one exists. The preview shows how many of your hashtags each platform keeps.
03
Long text or short caption
On TikTok, Reels, Threads and Snapchat the caption sits next to the video and is cut after the first line or so, the opening is the product. On YouTube, Facebook, LinkedIn and Pinterest the description is its own field with room, and search reads it.
So write both: a full description and a one-line hook. If you leave the hook empty, the preview cuts the description instead, which is what most schedulers do by default.
Sources and methodology
Numbers checked on October 8, 2026.
The text is formatted by the same server function Uplonic runs at publish time. Limits come from the platforms' API documentation: Threads 500 characters, Instagram 2,200 characters and 30 hashtags, TikTok 2,200, YouTube 5,000 bytes and a 100-character title. Pinterest's 500-character description is from secondary sources. Your text is not stored.
