Video publishing API for TikTok, Reels and YouTube

Upload once and publish everywhere, with each platform's own controls: covers, music, playlists, trial Reels and AI labels. Built for video generation and repurposing tools.

Start for free Read the docs

SOC 2
GDPR compliant
99.97% uptime
Under 50ms response

Join 200,000+ of the world's most ambitious developers and builders

Why Zernio?

Three video APIs to learn, or one request

Integrating YouTube, TikTok and Instagram yourself

Three upload flows
Each platform moves a video file its own way.
Three app reviews
Google, TikTok and Meta each approve you separately.
Files that get rejected
Size, length and format limits differ on every platform.
Three sets of options and errors
Covers, privacy and music all work differently.

One video API, on Zernio

One upload
Send the file once. We host it and deliver it to each platform.
Files checked before they post
Each video is compared with every platform's size limits first.
Every native control kept
Covers, music, playlists, trial Reels and AI labels in the same request.
Approvals already done
Official platform APIs, through Zernio's approved apps.

How It Works

From rendered file to live video in three steps

POST /v1/media/presign

spring-drop.mp4 · 412 MB

Uploaded

publicUrl

Upload the file, or point to it

Upload up to 5 GB straight to Zernio, or pass a link to where the video already lives.

POST /v1/posts

3 accounts

coverplaylistAI label

Publish with each platform's options

One request carries the video, the caption and the per-platform settings. Zernio checks the file and runs each platform's upload.

webhook · post.publishedlive

TikTok · 31.9K viewsanalytics

Get the link and the numbers back

A webhook returns each live video's link, or the reason it failed. Analytics follow, video by video.

What you can build

Real video features for each platform, not a lowest common denominator

TikTok

cover frameCommercial Musicduet + stitchAI label

Instagram Reels

trial Reelcatalog audiocollaboratorsshare to feed

YouTube

Shortsplaylistvisibilitymade for kidsthumbnail

Every native control, in one request

Set what each platform offers for video, side by side, without learning three APIs.

spring-drop.mp4

412 MB · 00:24 · 1080 × 1920

TikTokWithin limits

InstagramWithin limits

YouTubeVertical, 00:24: a Short

Uploads and file checks handled

Zernio hosts the file and compares it with each platform's limits. Media over a limit is compressed where it can be.

YouTube

Vertical videos of 3 minutes or less become Shorts. Titles, visibility, playlists, categories and thumbnails, plus caption tracks you can read back.

TikTok

Cover frames, Commercial Music tracks, duet and stitch settings, AI labels, and drafts sent to the creator's inbox.

Instagram

Reels and Stories, trial Reels, catalog audio, collaborators, custom covers and paid partnership labels.

“Zernio is a great tool meant for developers, built by developers. That's what's groundbreaking versus the competition. There's no one in the middle, we can talk engineer to engineer and just ship immediately.”

Sergio CayeroHead of Product, Plinng

Read the full story

Instagram connected inside Plinng through the Zernio API

3 hours to ship the Instagram integration

Build it in code

One request per video. We carry the rest.

Uploads, file limits, platform approvals, token refresh and API changes are ours. One REST API and 8 SDKs are yours.

Read the docs

POST /v1/posts

# one request, trimmed to the video options
curl -X POST https://zernio.com/api/v1/posts \
  -d '{
  "mediaItems": [{ "type": "video", "url": "..." }],
  "platforms": [
   { "platform": "tiktok", "platformSpecificData": {
       "videoCoverTimestampMs": 3000,
       "videoMadeWithAi": true } },
   { "platform": "instagram", "platformSpecificData": {
       "shareToFeed": true, "isAiGenerated": true } },
   { "platform": "youtube", "platformSpecificData": {
       "visibility": "unlisted",
       "playlistId": "PL...",
       "containsSyntheticMedia": true } }
  ]}'

Build it with an agent

Or give your content to your agent

If an agent already makes the content, the Zernio MCP server lets it publish, check results and decide what to make next.

See how agents connect

content agent

> publish today's three clips to
  TikTok and YouTube Shorts

call_tool · validate_media · 3 files
call_tool · posts_create · 6 posts
done · 6 published, links returned

> which of last week's clips did best?

call_tool · analytics · 21 posts
done · "spring-drop" led with 31.9K views

What it costs

You pay per connected account. Never per video.

Start with two accounts for free. An account that publishes ten videos a day costs the same as one that publishes two.

Your tool

Connected accountsEach TikTok, Instagram or YouTube channel your users connect

1101501.5k15k

Videos per account, each weekChanges the volume, never the bill

13143570

ZernioFreefirst 2 accounts

Per video$030 videos a month

Your first two accounts are free, with every feature.

First 2 accounts: Free
3 to 10: $6 each
11 to 100: $3 each
101 and up: $1 each

Posts are never billed. Each platform caps daily volume per account, for example 15 videos a day on TikTok and 100 posts on Instagram. Ad accounts count as connected accounts.

Start for free See pricing