Video Limits Schedulers Set on Each Network
A scheduled video has to clear two ceilings: your scheduler's upload cap and the network's own cap. Buffer lists X at 1GB and, on the same page, X itself at 512MB. Publer publishes Mastodon video at under 40 MB in one place and less than 99 MB in another. Documentation read November 3, 2026.
This article is a documentation review: it is based on the vendors' own published pages, checked on the date shown. We may earn a commission from some links; it never affects what we recommend.
A video can clear your scheduler's upload check and still fail at the network, because the two ceilings are set by different people. Buffer and Publer both publish their own numbers, and the numbers do not match.
Buffer's video article lists X/Twitter at 1GB, then states on the same page that X itself accepts 512MB. Publer's developer docs list X at under 512 MB.
Both pages were read on November 3, 2026. Neither vendor is wrong. One is quoting its own upload limit and the other is quoting the network's.
A scheduler's upload cap is not the network's cap
Buffer's own limit is the first gate. Its page lists 300MB for Instagram, 10GB for YouTube Shorts, 40MB for Mastodon, up to 100MB for Bluesky, and up to 1GB for Facebook, X, LinkedIn, Pinterest, TikTok, Threads and Substack.
The LinkedIn row says so outright. Buffer writes that 1 GB "is Buffer's upload limit for LinkedIn" and that LinkedIn's own platform supports larger files natively.
The X row is where the gap bites. Buffer lists 1GB, then says a video publishes natively only if it is within X's permitted file limits of 512MB and between .5 seconds and 140 seconds long.
Outside that window the post still goes out. Buffer states the video will be displayed as a link to Buffer's video player instead of playing in the feed.
That is a quiet downgrade rather than an error. It does not arrive as a failed post, which is the category described in what a social scheduler does when a post fails.
Publer's two documentation pages disagree with each other
Publer publishes these limits in two places and the numbers differ. Its developer docs list Mastodon video at under 40 MB. Its help center article lists Mastodon video at less than 99 MB.
Bluesky splits the same way. The developer docs say under 50 MB; the help center article says no bigger than 100MB. Both were read on November 3, 2026.
Where a vendor contradicts itself, plan for the smaller figure. A 60 MB Mastodon clip sits inside one published limit and outside the other.
- Facebook: standard video up to 5 hours and under 2 GB, Reels 3 to 90 seconds. Both Publer pages agree here.
- Instagram Reels: 3 seconds to 15 minutes and under 1 GB on Publer, against below 300MB on Buffer.
- X: under 512 MB and under 10 minutes on Publer, rising to 120 minutes with an X Premium subscription.
- LinkedIn: 3 seconds to 15 minutes and up to 2 GB on Publer, against Buffer's stated 1 GB cap.
- YouTube: standard video up to 12 hours and 2 GB on Publer, with Shorts up to 3 minutes.
- TikTok: 3 seconds to 10 minutes on both pages, but no bigger than 2 GB on Publer and 1GB or less on Buffer.
Length limits diverge further than file size limits
The widest single gap in this set is X video length. Buffer lists .5 seconds to 140 seconds. Publer lists up to 10 minutes, or up to 120 minutes on X Premium.
So a four minute clip is schedulable on one tool and not the other, for the same account on the same network. Check your own tool's page before building a format around it.
YouTube Shorts runs the other way. Both vendors cap length at 3 minutes, while Buffer allows a 10GB file and Publer allows under 2 GB.
Publer adds an operational note on Shorts. It states that YouTube Shorts longer than 1 minute may take a week before they show up as Shorts on YouTube.
Network-side ceilings sit underneath all of this. The published API limits are collected in Instagram and TikTok API limits for schedulers and LinkedIn and X API limits for schedulers.
The scheduler re-encodes your file before the network sees it
Buffer describes its own pipeline. An uploaded file is checked against the API, handed to Amazon Web Services for transcoding, and then used to generate candidate thumbnails.
Thumbnail generation is sampled by time. Buffer looks for a different thumbnail every 15 seconds, so a 30 minute video means at least 120 generated images and a slower upload.
Mastodon video is re-encoded outright. Buffer states it is transcoded to H.264 MP4 with a maximum bitrate of 1300kbps and a frame rate of 60fps.
Buffer also sets a hard pixel ceiling there. Total pixel count cannot exceed 8,294,400 pixels, and a 3024 x 4032 file shows a validation error in the composer before you can schedule it.
One format decision is made for you on Facebook. Buffer notes that due to API limitations, any video uploaded to Facebook with a 9:16 aspect ratio will get published as a Reel.
Still images get the same treatment. Publer states Bluesky photos are limited to 1 MB and larger sizes will be compressed by Publer, while Buffer says it cannot resize Bluesky images at all.
At least one network meters video by the day
Bluesky is capped per day as well as per post. Buffer lists a daily limit of 25 videos per day, or a total of 10GB of videos sent within a day, whichever comes first.
That is a separate meter from your plan's post allowance. Plan-level ceilings are covered in how many scheduled posts each plan allows and what a daily posting limit means.
What we could not read on the day
Later's help center returned a Cloudflare security check on November 3, 2026, with a Ray ID and no article content. No Later figure appears in this article.
SocialBee and Vista Social failed the same way. One returned an empty response and the other returned the same security check. That is a reading failure on our side, not a claim about either vendor.
Buffer's own page groups Pinterest with the 1GB networks at the top but prints no size inside the Pinterest section. Only the length range, 4 seconds to 15 minutes, appears there.
What to check before you schedule a video
- Export under your scheduler's cap and under the network's cap, whichever of the two is lower.
- For X, assume 512MB and 140 seconds unless your own tool's page says otherwise today.
- When one vendor publishes two different figures, build to the smaller one.
- Expect re-encoding. Bitrate, frame rate and pixel ceilings apply after upload, not before.
- Check per-day video caps separately from per-plan post caps. Bluesky has both.
- Re-read the page before a campaign. Both vendors change these numbers without notice.
Plan pages carry the same reading problem as media pages. How to read a social tool pricing page and Publer vs Buffer paid tiers cover the commercial side of the same two vendors.
If a design tool sits upstream of your exports, Canva free vs Pro for social posts lists what the free tier allows. Channel counting is in what counts as a channel in social tools.
Frequently asked questions
What is the maximum video length for a scheduled X post?
The two vendors disagree. Buffer lists .5 seconds to 140 seconds; Publer lists up to 10 minutes, or 120 minutes with X Premium. Both pages were read November 3, 2026, so confirm in your own composer.
Why did my video post as a link instead of a video?
On X through Buffer, a file outside X's permitted limits of 512MB and .5 to 140 seconds is published as a link to Buffer's video player rather than natively, per Buffer's video article read November 3, 2026.
Does a scheduler compress my video?
Buffer states uploaded files are transcoded by Amazon Web Services, and that Mastodon video is converted to H.264 MP4 at a maximum 1300kbps bitrate and 60fps. Publer compresses Bluesky photos over 1 MB.
What is the largest file I can schedule?
On Buffer's list the largest is YouTube Shorts at 10GB or less, read November 3, 2026. Publer's developer docs cap YouTube at under 2 GB, so the answer depends on which tool you use.
Is there a daily limit on scheduled videos?
On Bluesky, yes. Buffer lists 25 videos per day or 10GB of videos within a day, whichever comes first. No other network in Buffer's list carries a published daily video cap.
Why does Publer list two different Mastodon limits?
We cannot say. Its developer docs list under 40 MB and its help center article lists less than 99 MB, both read November 3, 2026. Build to 40 MB until the pages agree.
Bottom line
Treat your scheduler's upload cap as a separate number from the network's. Buffer says so explicitly for LinkedIn, and the gap on X changes how the post renders rather than whether it sends.
Where one vendor publishes two values for the same network, the smaller one is the safe build target. That applies to Publer on Mastodon and Bluesky as of November 3, 2026.
All figures here come from the vendors' own published pages as read on November 3, 2026, and can change without notice. Confirm the limits in your composer before a launch depends on them.
Sources
- Buffer: Sharing videos through Buffer (per-network size, length, aspect ratio, transcoding and thumbnail notes, Bluesky daily video cap) (checked Nov 3, 2026)
- Publer developer docs: Video Posts (per-network duration, size limit and aspect ratio table) (checked Nov 3, 2026)
- Publer help center: What post types are supported and what are their limitations (per-network video, photo and GIF limits) (checked Nov 3, 2026)
- Later help center: Video Upload Requirements (returned a Cloudflare security check, no figure readable) (checked Nov 3, 2026)