Video specs for TikTok, X and LinkedIn

TikTok's Content Posting API takes videos up to 4 GB at 23 to 60 fps. X's app allows 2:20 without Premium. LinkedIn's API takes MP4, 3 seconds to 30 minutes, 75 KB to 500 MB. App and API limits differ: LinkedIn's app takes a 5 GB file, while developers report X's API refusing videos over 2:20 even from Premium accounts.

Specifications checked on October 28, 2026, against each network's own help pages and developer docs, linked under Sources. The networks change these without notice, so check them again before you build on one.

For photos, see social media image sizes.

One file for all three

Start with these shared settings, then check the account and posting route below. They aren't a guarantee of acceptance: X's own pages conflict, and TikTok's length allowance depends on the creator.

• MP4, with H.264 video (High Profile) in 4:2:0 colour and square pixels, and AAC-LC sound in mono or stereo.
• 3 seconds to 2:20 long. LinkedIn needs at least 3 seconds; X stops at 2:20 (140 seconds) without Premium.
• 75 KB to 500 MB. LinkedIn's API has the lowest ceiling.
• 1280 × 720 or 720 × 720 pixels. These fit the listed dimension ranges. X's API also recommends 720 × 1280 for portrait, despite listing a 1280 × 1024 ceiling elsewhere on the same page. TikTok recommends 1080p or more for its own uploads, and X plays 1080p from subscribed accounts.
• An aspect ratio between 1:2.39 and 2.39:1, X's web upload being the narrowest. 9:16, 1:1 and 16:9 all fit.
• 24, 25 or 30 fps. TikTok's API needs at least 23, and X's web upload takes at most 40.
• Under 25 Mbps, X's web limit, and over LinkedIn's 192 Kbps.

This ffmpeg line makes that format from most files. It keeps the picture size and the length, so trim and resize separately (to turn 1080 × 1920 into 720 × 1280, start the filter with scale=-2:1280,). CRF encoding doesn't cap the file size or bitrate; check both afterwards:

ffmpeg -i input.mov -vf fps=30,setsar=1 -c:v libx264 -profile:v high -pix_fmt yuv420p -crf 20 \
  -c:a aac -b:a 128k -ac 2 -movflags +faststart video.mp4

X (Twitter)

X's help counts the Plus, Premium, Super and Ultra plans on The X Subscription as Premium for longer videos. Its app also supports posts with multiple videos or a video and an image. Flaghand's single-video rule below is its own, not a general X app limit.

The X API and 2:20

X's media docs give a post's video 20 minutes without Premium, and also say "Post-video caps match the X app", whose cap without a subscription is 140 seconds. Developers on X's forum report the API holding accounts to that, Premium ones included: the upload finishes, then POST /2/tweets answers 403 with "This user is not allowed to post a video longer than 2 minutes." The reports run from May 2025 to May 2026, for videos the same accounts could post in the app. X checks the limits twice, when you upload and again when the post is created, so a finished upload is no promise. Keep API videos to 2:20 until your account has posted a longer one through the API.

LinkedIn

• One video per post, on its own. LinkedIn's help says so for the app, and the API's post takes one video.
• Page and Career Page videos have a separate help article, listing 10 minutes and excluding AVI, QuickTime and MOV. It links to editing the Life / What We Do tab's main video; don't treat its 10 minutes as a universal Page-feed posting limit.
• The API's 500 MB. The Videos API's specifications say 75 KB to 500 MB. The same page's upload field, fileSizeBytes, gives 5 GB as the largest allowed. Keep API videos to 500 MB.
• API uploads go in 4 MB parts. initializeUpload returns one upload URL per 4,194,304-byte range. Each part's PUT returns an ETag, and finalizeUpload takes them in the same order. The URLs usually expire 30 days after the upload starts. A video can have one caption file (English only) and a thumbnail. Every request, in order, is in posting images and video through LinkedIn's API.

TikTok

• Web upload versus phone recording. The app column describes TikTok Studio's web uploader. Recording in the phone app, you pick a maximum length first; don't assume that recording and uploading have the same limit.
• Each account's own limit. The API's creator info call returns max_video_post_duration_sec, "the longest video duration in seconds that the TikTok creator can post". Read it before each post rather than assuming 10 minutes.
• Upload in chunks. Each chunk is 5 MB to 64 MB, sent in order, and the last can be up to 128 MB to take the trailing bytes. A video under 5 MB goes in one piece; one over 64 MB must go in several; 1 to 1,000 chunks in all.

What Flaghand checks

Flaghand is a publishing desk where your agent drafts the post and you approve it. Its own upload limit is smaller than any network's, so here it is plainly:

• Uploads are MP4 or MOV, up to 50 MB. Longer or high-bitrate videos need compressing first. Check the output's size after encoding; the ffmpeg line above doesn't enforce a file-size ceiling.
• LinkedIn: before you approve, the check applies the Videos API's rules: MP4 only, 75 KB to 500 MB, 3 seconds to 30 minutes, one video on its own and no link card.
• X: one video per post, not mixed with photos. X makes its own length and format checks when Flaghand uploads and posts, and if X refuses the video, the job fails and says so.
• TikTok: the video goes to TikTok in one piece of up to 64 MB, and the check compares its length with the account's longest from TikTok's creator info. TikTok inbox drafts are in beta; public Direct Post waits for TikTok's audit.
• You approve the exact post. Agent tokens can't approve, schedule or post. The owner approves in the desk with a passkey, and the approval covers the exact video, text and time.

Flaghand is in early access, so sign-up isn't open yet. Every media field is in Flaghand's drafts and media docs. Get access to Flaghand.