TikTok's Content Posting API is unusual in two ways: it checks some rules after the upload, hours later, and it applies a per-creator limit on video length that only the API can tell you. A scheduler that reads the published limits and nothing else will report success on a post that TikTok then drops.
Video
| Rule | |
|---|---|
| Length | 3 seconds to 10 minutes through the API, and no longer than the creator's own maximum (3, 5 or 10 minutes), which the API reports per account |
| Size | 4 GB |
| Frame rate | 23 to 60 fps; checked after processing, failure arrives later as "frame rate check failed" |
| Resolution | 360 to 4,096 pixels on each side |
| Format | MP4, MOV, WebM; H.264 or H.265, AAC |
| Ratio | 9:16 recommended; others are letterboxed |
The frame rate is the rule that ruins mornings: a phone recording at 120 fps or a screen capture at 15 fps uploads fine, the tool says "published", and the video is gone the next day. The fix is to read the file's frame rate before upload and refuse it. The per-creator maximum is the other: a new account may be limited to 3 minutes while the documentation says 10.
Caption
| Rule | |
|---|---|
| Video caption | 2,200 characters |
| Photo post caption | 4,000 characters |
| Photo post title | The first line; TikTok shows 90 characters |
| Hashtags | Written as #tag in the caption; TikTok makes them live |
Photo posts
| Rule | |
|---|---|
| Pictures | Up to 35 |
| Format | JPEG or WebP, up to 1080p; TikTok pulls the pictures from a URL on a host verified in the developer console, so the tool has to serve them from a domain it has verified |
| Cover | Any one of the pictures |
| Music | TikTok adds its own unless told not to |
Settings the API requires
Every post must say who can see it (public, friends, only me), whether comments, duets and stitches are allowed, whether it is branded content or a promotion, and whether it contains AI-generated content. A tool that leaves privacy unset posts as only me and the video is invisible. TikTok's review of an app checks that the tool shows the creator's current settings and makes the choice explicit.
Direct or inbox
The API can publish directly with the settings above, or send the video to the creator's TikTok inbox as a draft to finish in the app. The inbox route is what a tool that has not passed TikTok's audit is limited to.
Figures
Views, likes, comments and shares per video, and the account's follower count, through the API. No comments inbox: TikTok's API does not read or write comments for third-party tools.
What Preflight checks before upload
Length against 10 minutes and against the creator's own maximum read from TikTok, size, frame rate between 23 and 60, resolution between 360 and 4,096, format, caption length by post type, the 35-picture limit, and that privacy is chosen. Photo posts are served from a verified domain as JPEG fitted to 1080p.
Rules from TikTok's Content Posting API documentation and Preflight's publishing, checked 5 October 2026. All networks: the limits page.
Questions people ask
- What frame rate does TikTok accept?
- 23 to 60 fps. Anything outside fails after processing, often hours after upload. Convert 120 fps phone video to 60 or 30 first.
- How long can a TikTok video be through the API?
- Up to 10 minutes, but each creator has its own maximum (3, 5 or 10 minutes) that the API reports for the account. The lower one applies.
- Why did my scheduled TikTok post appear as 'only me'?
- The tool did not set the privacy level. TikTok's API defaults to private when a tool omits it; choose public explicitly.