Posting by API - the limits sheet for Instagram, Facebook, LinkedIn and TikTok
The numbers that decide what you can publish through official APIs: carousel sizes, video lengths, document pages, caption limits. Each with its source.
Read on 2026-10-10 from official developer documentation. Platforms change these; check the source before you build on a number.
Instagram (Graph API)
| What | Limit | Source |
|---|---|---|
| Carousel items | up to 10 images, videos or a mix | Content Publishing |
| Reels in a carousel | not allowed ("Reels cannot appear in carousels") | IG User Media |
| Carousel cropping | all items cropped to the first item; default 1:1 | Content Publishing |
| Feed image aspect ratio | 4:5 to 1.91:1, JPEG, max 8 MB | IG User Media |
| Reel video | 3 s to 15 min, max 300 MB, 23-60 fps, MP4/MOV, H.264 or HEVC; 9:16 recommended | IG User Media |
| Caption | max 2,200 characters, 30 hashtags, 20 @tags | IG User Media |
| Publishing quota | the page lists both 100 and 50 API posts per 24 h; a carousel counts as one | Content Publishing |
The Instagram app itself allows up to 20 items per carousel (rolled out from August 2024, per press coverage); the API stays at 10.
Facebook Page
| What | Limit | Source |
|---|---|---|
| Reels | 9:16, 1080×1920 recommended (min 540×960), 24-60 fps, 3 to 90 s | Reels Publishing API |
| Feed video | regular Page video upload (Video API) | Pages API: Posts |
Swipeable carousels of several videos are documented for ads. Third-party scheduling tools report that organic Page posts don't support multi-video carousels; we found no official statement either way.
LinkedIn (Posts API, Community Management)
| What | Limit | Source |
|---|---|---|
| Document post | PDF, PPT, PPTX, DOC, DOCX; max 100 MB and 300 pages | Documents API |
| Multi-image post | 2 to 20 images; JPG, PNG, GIF (GIF up to 250 frames) | MultiImage API |
| Video | 3 s to 30 min, 75 KB to 500 MB | Videos API |
| API version | Marketing version 202510 is sunset on 2026-10-15; send a current Linkedin-Version header (YYYYMM) | Docs banner |
A document post swipes page by page like a carousel, but the pages are still images. A multi-image post shows as a grid, not a swipe.
TikTok (Content Posting API)
| What | Limit | Source |
|---|---|---|
| Photo post | up to 35 images; title up to 90, description up to 4,000 UTF-16 units | Photo post reference |
| Unaudited apps | "All content posted by unaudited clients will be restricted to private viewing mode" | Photo post reference |
Sources
- developers.facebook.com: Instagram Platform "Content Publishing"; "IG User Media" reference; Video API "Reels Publishing"; Pages API "Posts". Read 2026-10-10.
- learn.microsoft.com: LinkedIn Documents API, MultiImage API, Videos API (li-lms-2026-09). Read 2026-10-10.
- developers.tiktok.com: Content Posting API, photo post reference. Read 2026-10-10.
- Instagram 20-item carousels: press coverage of the August 2024 rollout (e.g. businesstoday.in, metricool.com); official post not found.
Made by SocialOS. SocialOS publishes to Instagram, Facebook and LinkedIn through these official APIs.
Keep reading
A 10-point check for your Instagram or Facebook profile
Ten checks a small business can do in one evening, in the order that matters, with what to fix first.
15 checks before you automate DMs from comments
A pre-flight list for "comment a keyword, get a link" on Instagram: Meta's rules, GDPR basics, and the things that break in practice.
Comment-to-DM message kit - public replies, opening DM, reward, STOP
Copy-ready texts for every step of a "comment a keyword, get a link" flow, within Meta's limits, in English with Polish and Ukrainian versions of the key lines.