What is the character limit on X?

280 characters, links included. Long-form posts are available to paid accounts, but 280 is what the standard API accepts.

What is the Instagram caption limit?

2,200 characters. In practice captions under about 100 characters see more engagement, and up to 5 hashtags at the end is the convention.

Can I post text only to Instagram or TikTok?

No to both. Instagram requires a photo or video, and TikTok's Content Posting API publishes video only — photos go through a separate flow. LinkedIn, X, Bluesky, Mastodon, Telegram and Discord all accept text on its own.

What is the best aspect ratio for cross-posting?

9:16 vertical travels furthest: it is native for TikTok, Reels and Shorts. For LinkedIn, Facebook and Instagram feed, 1:1 or 4:5 uses more screen than 16:9.

Character limits and post sizes, per network

Short answer. These are the values our publishing engine enforces before it sends anything, so they are the ones that get posts rejected rather than merely truncated. The two that surprise people most: TikTok and YouTube accept nothing but video, and Instagram refuses text-only posts entirely.

Limits and prices checked against live APIs and vendor pricing pages on 23 August 2026.

Every network at a glance

Network	Characters	Media	Aspect ratio	Notes
TikTok	2,200	video only	9:16 vertical	Max 5 hashtags, in the caption — comments are invisible to the algorithm.
Instagram	2,200	photo or video, never text-only	9:16 Reels · 1:1 or 4:5 feed	Short captions under ~100 chars get more engagement; max 5 hashtags at the end.
YouTube	5,000	video only	16:9 long-form · 9:16 Shorts	Title max 100 chars — keyword in the first 40. 5-8 backend tags.
LinkedIn	3,000	optional	1:1 or 4:5	Only ~210 chars show before the fold. External links suppress reach — put them in a comment.
X	280	optional	16:9 or 1:1	The whole post is the hook. Links reduce reach; put them in a reply.
Facebook	2,000	optional	1:1 or 4:5	40-80 chars peaks engagement; mobile cuts at ~125.
Threads	500	optional	1:1 or 4:5	Conversational; long posts get collapsed.
Bluesky	300	optional	16:9 or 1:1	300 characters total, links included.
Mastodon	500	optional	16:9 or 1:1	500 on most instances, but the server decides — some allow more.
Reddit	10,000	optional	any	Title max 300 chars. Each subreddit has its own rules and they are enforced by humans.
Telegram	4,000	optional	any	4096 characters per message.
Discord	2,000	optional	any	2000 per message on a free server.

Limits that reject, versus limits that truncate

Worth separating. Going over a character limit is usually a rejection from the API, not a silent cut — you get an error and no post. Media rules are always rejections: send a photo to TikTok and you get tiktok requires a video_url, because photo posts use a different flow entirely. Aspect ratios are the soft ones: the wrong ratio still publishes, it just gets cropped or letterboxed, and vertical video is what the feeds reward.

The values change, and the server sometimes decides

Mastodon is the clearest example: 500 characters is the default, but each instance sets its own, and some allow far more. Reddit's limits are the least of your problems there — each subreddit adds rules enforced by humans. Everything above was checked against live APIs in August 2026; when a platform moves, the error message is the source of truth.

Start free — 1 brand, all its networks, no card

30 posts a month on the free plan. Starter is $9/month for three brands and 300 posts; Pro $29 for ten brands and 2,000. Flat per-account pricing — no per-network fee.

Questions people ask

What is the character limit on X?: 280 characters, links included. Long-form posts are available to paid accounts, but 280 is what the standard API accepts.
What is the Instagram caption limit?: 2,200 characters. In practice captions under about 100 characters see more engagement, and up to 5 hashtags at the end is the convention.
Can I post text only to Instagram or TikTok?: No to both. Instagram requires a photo or video, and TikTok's Content Posting API publishes video only — photos go through a separate flow. LinkedIn, X, Bluesky, Mastodon, Telegram and Discord all accept text on its own.
What is the best aspect ratio for cross-posting?: 9:16 vertical travels furthest: it is native for TikTok, Reels and Shorts. For LinkedIn, Facebook and Instagram feed, 1:1 or 4:5 uses more screen than 16:9.