Documentation index for AI agents: https://bynor.ai/llms.txt. Full text of this guide in one file: https://bynor.ai/llms-full.txt.

Guide

Formats and limits per network

What you can publish from Bynor on Instagram, Facebook, TikTok, YouTube and LinkedIn, with caption length limits, carousel slide limits and maximum file sizes.

Updated · 3 min read

In short

From Bynor you publish posts, carousels, Reels and Stories on Instagram; photos, photo carousels, videos, Reels and Stories on Facebook; videos and photo carousels on TikTok; Shorts on YouTube; text, images, image collages, videos and PDF documents on LinkedIn. Captions over the network's limit are stopped when you schedule. Carousels go up to 10 slides on Instagram, 15 on Facebook, 20 on LinkedIn and 35 on TikTok.

What you can publish

NetworkFormats available from Bynor
InstagramPhoto post, carousel (photos and videos), Reel, Story, Trial Reel
FacebookPhoto, photo carousel, video and Reel, Story
TikTokVideo, photo carousel
YouTubeShort (vertical video up to 3 minutes)
LinkedInText post, image, image collage, video, PDF document (carousel)

Caption length

Network and formatMaximum characters
Instagram post, carousel, Reel2,200
Instagram StoryNo caption
Facebook post and Reel63,206
Facebook StoryNo caption
TikTok video (title)2,200
TikTok photo carousel4,000
YouTube (description)5,000 bytes: emoji and accented letters count as more than one. The title is cut at 100 characters
LinkedIn3,000

If a caption is longer than the limit, Bynor stops it when you schedule the post and asks you to shorten it. TikTok removes line breaks from captions.

Carousels

NetworkSlidesContent
Instagram2 to 10Photos and videos (each video up to 60 seconds)
Facebook2 to 15Photos only
TikTok2 to 35Photos only
LinkedIn2 to 20Images only, published as a PDF document or as an image collage
YouTubeNot available

File size when publishing

Bynor compresses videos so they stay within these limits; on Instagram and Facebook, videos over 100 MB are compressed further. When one post goes to several networks, the smallest limit applies.

Network and formatSize
Instagram post and Reel300 MB
Instagram Story100 MB
Facebook post, video and Reel500 MB
Facebook Story100 MB
TikTok video500 MB
YouTube Short500 MB
LinkedIn video500 MB

A LinkedIn PDF document can be up to 100 MB. You can upload files up to 2 GB to Post Pilot; the sizes above apply when the post goes out.

Other rules to know

  • Instagram feed photos look best at 4:5 (1080×1350). Reels and Stories are vertical, 9:16.
  • Stories contain one image or one video.
  • YouTube: Bynor publishes only Shorts, vertical videos up to 3 minutes. Horizontal videos and photos are not accepted.
  • TikTok asks you to choose the privacy level of every video.
  • LinkedIn videos last 3 seconds to 30 minutes. A LinkedIn carousel goes out by default as a PDF document that people swipe through in the feed; in the post you can switch Format to Image collage. The Document title (up to 100 characters) appears above the slides; if you leave it empty, Bynor uses the first line of the caption.
  • Instagram requires a professional account (Business or Creator).

Frequently asked questions

What is the caption limit on Instagram?

2,200 characters for posts, carousels and Reels. Stories have no caption.

Can I publish a photo on YouTube?

No. On YouTube Bynor publishes only Shorts, vertical videos up to 3 minutes.

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