Schedule and automate Instagram posts with Zernio API - Feed, Stories, Reels, Carousels, collaborators, and user tags

Quick Reference

Property	Value
Character limit	2,200 (caption)
Images per post	1 (feed), 10 (carousel)
Videos per post	1
Image formats	JPEG, PNG
Image max size	8 MB (auto-compressed)
Video formats	MP4, MOV
Video max size	300 MB (feed/reels), 100 MB (stories)
Video max duration	90 sec (reels), 60 min (feed), 60 sec (story)
Post types	Feed, Carousel, Story, Reel
Scheduling	Yes
Inbox (DMs)	Yes (add-on)
Inbox (Comments)	Yes (add-on, reply-only)
Analytics	Yes

Before You Start

Instagram requires a Business or Creator account. Personal accounts cannot post via API.

Google Drive, Dropbox, OneDrive, and iCloud links do not work as media URLs. These services return HTML pages, not media files. Instagram's servers cannot fetch media from them. Use direct CDN URLs or upload via Zernio's media endpoint.

Additional requirements:

Media is required for all posts (no text-only)
100 posts per 24-hour rolling window (all content types combined)
First 125 characters of caption are visible before the "more" fold

Quick Start

Post an image to Instagram in under 60 seconds:

const { post } = await zernio.posts.createPost({
  content: 'Check out this photo!',
  mediaItems: [
    { type: 'image', url: 'https://cdn.example.com/photo.jpg' }
  ],
  platforms: [
    { platform: 'instagram', accountId: 'YOUR_ACCOUNT_ID' }
  ],
  publishNow: true
});
console.log('Posted to Instagram!', post._id);

result = client.posts.create(
    content="Check out this photo!",
    media_items=[
        {"type": "image", "url": "https://cdn.example.com/photo.jpg"}
    ],
    platforms=[
        {"platform": "instagram", "accountId": "YOUR_ACCOUNT_ID"}
    ],
    publish_now=True
)
post = result.post
print(f"Posted to Instagram! {post['_id']}")

curl -X POST https://zernio.com/api/v1/posts \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Check out this photo!",
    "mediaItems": [
      {"type": "image", "url": "https://cdn.example.com/photo.jpg"}
    ],
    "platforms": [
      {"platform": "instagram", "accountId": "YOUR_ACCOUNT_ID"}
    ],
    "publishNow": true
  }'

Content Types

Feed Post

A single image or video in the main feed. Best aspect ratio is 4:5 (portrait), but 1:1 (square) and 1.91:1 (landscape) are also supported. No contentType field is needed -- feed is the default.

const { post } = await zernio.posts.createPost({
  content: 'Beautiful sunset today #photography',
  mediaItems: [
    { type: 'image', url: 'https://cdn.example.com/sunset.jpg' }
  ],
  platforms: [
    { platform: 'instagram', accountId: 'YOUR_ACCOUNT_ID' }
  ],
  publishNow: true
});
console.log('Feed post created!', post._id);

result = client.posts.create(
    content="Beautiful sunset today #photography",
    media_items=[
        {"type": "image", "url": "https://cdn.example.com/sunset.jpg"}
    ],
    platforms=[
        {"platform": "instagram", "accountId": "YOUR_ACCOUNT_ID"}
    ],
    publish_now=True
)
post = result.post
print(f"Feed post created! {post['_id']}")

curl -X POST https://zernio.com/api/v1/posts \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Beautiful sunset today #photography",
    "mediaItems": [
      {"type": "image", "url": "https://cdn.example.com/sunset.jpg"}
    ],
    "platforms": [
      {"platform": "instagram", "accountId": "YOUR_ACCOUNT_ID"}
    ],
    "publishNow": true
  }'

Carousel

Up to 10 mixed image/video items. All items should share the same aspect ratio -- the first item determines the ratio for the entire carousel.

const { post } = await zernio.posts.createPost({
  content: 'Trip highlights from last weekend',
  mediaItems: [
    { type: 'image', url: 'https://cdn.example.com/photo1.jpg' },
    { type: 'image', url: 'https://cdn.example.com/photo2.jpg' },
    { type: 'video', url: 'https://cdn.example.com/clip.mp4' },
    { type: 'image', url: 'https://cdn.example.com/photo3.jpg' }
  ],
  platforms: [
    { platform: 'instagram', accountId: 'YOUR_ACCOUNT_ID' }
  ],
  publishNow: true
});
console.log('Carousel posted!', post._id);

result = client.posts.create(
    content="Trip highlights from last weekend",
    media_items=[
        {"type": "image", "url": "https://cdn.example.com/photo1.jpg"},
        {"type": "image", "url": "https://cdn.example.com/photo2.jpg"},
        {"type": "video", "url": "https://cdn.example.com/clip.mp4"},
        {"type": "image", "url": "https://cdn.example.com/photo3.jpg"}
    ],
    platforms=[
        {"platform": "instagram", "accountId": "YOUR_ACCOUNT_ID"}
    ],
    publish_now=True
)
post = result.post
print(f"Carousel posted! {post['_id']}")

curl -X POST https://zernio.com/api/v1/posts \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Trip highlights from last weekend",
    "mediaItems": [
      {"type": "image", "url": "https://cdn.example.com/photo1.jpg"},
      {"type": "image", "url": "https://cdn.example.com/photo2.jpg"},
      {"type": "video", "url": "https://cdn.example.com/clip.mp4"},
      {"type": "image", "url": "https://cdn.example.com/photo3.jpg"}
    ],
    "platforms": [
      {"platform": "instagram", "accountId": "YOUR_ACCOUNT_ID"}
    ],
    "publishNow": true
  }'

Story

Set contentType: "story" to publish to Stories. Stories disappear after 24 hours, text captions are not displayed, and link stickers are not available via the API (this is a limitation of Instagram's Graph API, not Zernio).

const { post } = await zernio.posts.createPost({
  mediaItems: [
    { type: 'image', url: 'https://cdn.example.com/story.jpg' }
  ],
  platforms: [{
    platform: 'instagram',
    accountId: 'YOUR_ACCOUNT_ID',
    platformSpecificData: {
      contentType: 'story'
    }
  }],
  publishNow: true
});
console.log('Story posted!', post._id);

result = client.posts.create(
    media_items=[
        {"type": "image", "url": "https://cdn.example.com/story.jpg"}
    ],
    platforms=[{
        "platform": "instagram",
        "accountId": "YOUR_ACCOUNT_ID",
        "platformSpecificData": {
            "contentType": "story"
        }
    }],
    publish_now=True
)
post = result.post
print(f"Story posted! {post['_id']}")

curl -X POST https://zernio.com/api/v1/posts \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "mediaItems": [
      {"type": "image", "url": "https://cdn.example.com/story.jpg"}
    ],
    "platforms": [{
      "platform": "instagram",
      "accountId": "YOUR_ACCOUNT_ID",
      "platformSpecificData": {
        "contentType": "story"
      }
    }],
    "publishNow": true
  }'

Reel

Set contentType: "reels" to publish a Reel, or let Zernio auto-detect it from vertical 9:16 video under 90 seconds. Reels must be vertical (9:16) and no longer than 90 seconds.

const { post } = await zernio.posts.createPost({
  content: 'New tutorial is up!',
  mediaItems: [
    { type: 'video', url: 'https://cdn.example.com/reel.mp4' }
  ],
  platforms: [{
    platform: 'instagram',
    accountId: 'YOUR_ACCOUNT_ID',
    platformSpecificData: {
      contentType: 'reels',
      shareToFeed: true
    }
  }],
  publishNow: true
});
console.log('Reel posted!', post._id);

result = client.posts.create(
    content="New tutorial is up!",
    media_items=[
        {"type": "video", "url": "https://cdn.example.com/reel.mp4"}
    ],
    platforms=[{
        "platform": "instagram",
        "accountId": "YOUR_ACCOUNT_ID",
        "platformSpecificData": {
            "contentType": "reels",
            "shareToFeed": True
        }
    }],
    publish_now=True
)
post = result.post
print(f"Reel posted! {post['_id']}")

curl -X POST https://zernio.com/api/v1/posts \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "New tutorial is up!",
    "mediaItems": [
      {"type": "video", "url": "https://cdn.example.com/reel.mp4"}
    ],
    "platforms": [{
      "platform": "instagram",
      "accountId": "YOUR_ACCOUNT_ID",
      "platformSpecificData": {
        "contentType": "reels",
        "shareToFeed": true
      }
    }],
    "publishNow": true
  }'

Media Requirements

Images

Property	Feed Post	Story	Carousel
Max images	1	1	10
Formats	JPEG, PNG	JPEG, PNG	JPEG, PNG
Max file size	8 MB	8 MB	8 MB each
Recommended	1080 x 1350 px	1080 x 1920 px	1080 x 1080 px

Aspect Ratios

Orientation	Ratio	Dimensions	Notes
Portrait	4:5	1080 x 1350 px	Best engagement for feed posts
Square	1:1	1080 x 1080 px	Standard feed and carousel
Landscape	1.91:1	1080 x 566 px	Widest allowed for feed
Vertical	9:16	1080 x 1920 px	Stories and Reels only

Feed posts accept aspect ratios between 0.8 (4:5) and 1.91 (1.91:1). Images outside that range must be posted as Stories or Reels.

Videos

Property	Feed	Reel	Story
Formats	MP4, MOV	MP4, MOV	MP4, MOV
Max file size	300 MB	300 MB	100 MB
Max duration	60 min	90 sec	60 sec
Min duration	3 sec	3 sec	3 sec
Aspect ratio	4:5 to 1.91:1	9:16	9:16
Resolution	1080 px wide	1080 x 1920 px	1080 x 1920 px
Codec	H.264	H.264	H.264
Frame rate	30 fps	30 fps	30 fps

Oversized media is auto-compressed. Images above 8 MB, videos above 300 MB (feed/reels) or 100 MB (stories) are compressed automatically. Original files are preserved.

Platform-Specific Fields

All fields go inside platformSpecificData on the Instagram platform entry.

Field	Type	Default	Description
`contentType`	`"story"` \| `"reels"`	(feed)	Omit for regular feed post. Set to `"story"` for Stories or `"reels"` for Reels.
`shareToFeed`	boolean	`true`	Reel-specific. Set to `false` to show the Reel in the Reels tab only, not the main feed.
`collaborators`	Array<string>	--	Up to 3 usernames. Must be public Business/Creator accounts. Does not work with Stories.
`userTags`	Array<{username, x, y, mediaIndex?}>	--	Tag users in images (not videos). Coordinates are 0.0 to 1.0. `mediaIndex` targets a specific carousel slide (0-based, defaults to 0).
`trialParams`	{graduationStrategy}	--	Trial Reels, shown only to non-followers. `graduationStrategy` is `"MANUAL"` or `"SS_PERFORMANCE"` (auto-graduate if it performs well).
`thumbOffset`	number (ms)	`0`	Millisecond offset from video start to use as thumbnail. Ignored if `instagramThumbnail` is set.
`instagramThumbnail`	string (URL)	--	Custom thumbnail for Reels. JPEG or PNG, recommended 1080 x 1920 px. Takes priority over `thumbOffset`.
`audioName`	string	--	Custom audio name for Reels (replaces "Original Audio"). Can only be set at creation.
`firstComment`	string	--	Auto-posted as the first comment. Works with feed posts and carousels, not Stories. Useful for links since captions do not have clickable links.

Media URL Requirements

These do not work as media URLs:

Google Drive -- returns an HTML download page, not the file
Dropbox -- returns an HTML preview page
OneDrive / SharePoint -- returns HTML
iCloud -- returns HTML

Test your URL in an incognito browser window. If you see a webpage instead of the raw image or video, it will not work.

Media URLs must be:

Publicly accessible (no authentication required)
Returning actual media bytes with the correct Content-Type header
Not behind redirects that resolve to HTML pages
Hosted on a fast, reliable CDN

Supabase URLs: Zernio auto-proxies Supabase storage URLs, so they work without additional configuration.

Analytics

Requires Analytics add-on

Available metrics via the Analytics API:

Metric	Available
Impressions	✅
Reach	✅
Likes	✅
Comments	✅
Shares	✅
Saves	✅
Views	✅

const analytics = await zernio.analytics.getAnalytics({
  platform: 'instagram',
  fromDate: '2024-01-01',
  toDate: '2024-01-31'
});
console.log(analytics.posts);

analytics = client.analytics.get(
    platform="instagram",
    from_date="2024-01-01",
    to_date="2024-01-31"
)
print(analytics["posts"])

curl "https://zernio.com/api/v1/analytics?platform=instagram&fromDate=2024-01-01&toDate=2024-01-31" \
  -H "Authorization: Bearer YOUR_API_KEY"

What You Can't Do

These features are not available through Instagram's API:

Add music to Reels
Use story stickers (polls, questions, links, countdowns)
Add location tags
Go Live
Create Guides
Boost or promote posts
Apply filters
Tag products
Post to personal accounts (Business or Creator only)
Create top-level comments (reply-only through the API)

Common Errors

Instagram has a 10.2% failure rate across Zernio's platform (35,634 failures out of 348,438 attempts). Here are the most frequent errors and how to fix them:

Error	Meaning	Fix
"Cannot process video from this URL. Instagram cannot fetch videos from Google Drive, Dropbox, or OneDrive."	A cloud storage sharing link was used instead of a direct media URL	Use a direct CDN URL. Test in an incognito window -- if you see a webpage, it will not work.
"You have reached the maximum of 100 posts per day."	Instagram's hard 24-hour rolling limit	Reduce posting volume. This limit includes all content types (feed, stories, reels, carousels).
"Instagram blocked your request."	Automation detection triggered	Reduce posting frequency, vary content. Wait before retrying.
"Duplicate content detected."	Identical content was already published recently	Modify the caption or media before retrying.
"Media fetch failed, retrying... (failed after 3 attempts)"	Zernio could not download media from the provided URL	Verify the URL is publicly accessible and returns actual media bytes, not an HTML page.
"Instagram access token expired."	The OAuth token for this account has expired	Reconnect the account. Subscribe to the `account.disconnected` webhook to catch this proactively.

Inbox

Requires Inbox add-on — Build: +$10/mo · Accelerate: +$50/unit · Unlimited: +$1,000/mo

Instagram supports DMs and comments with some limitations.

Direct Messages

Feature	Supported
List conversations	✅
Fetch messages	✅
Send text messages	✅
Send attachments	✅ (images, videos, audio via URL)
Quick replies	✅ (up to 13, Meta quick_replies)
Buttons	✅ (up to 3, generic template)
Carousels	✅ (generic template, up to 10 elements)
Message tags	✅ (`HUMAN_AGENT` only)
Archive/unarchive	✅

Attachment limits: 8 MB images, 25 MB video/audio. Attachments are automatically uploaded to temp storage and sent as URLs.

Message tags: Use messageTag: "HUMAN_AGENT" with messagingType: "MESSAGE_TAG" to send messages outside the 24-hour messaging window.

Instagram Profile Data

Instagram conversations include an optional instagramProfile object on participants and webhook senders, useful for routing and automation:

Field	Type	Description
`isFollower`	boolean	Whether the participant follows your business account
`isFollowing`	boolean	Whether your business account follows the participant
`followerCount`	integer	The participant's follower count
`isVerified`	boolean	Whether the participant is a verified Instagram user
`fetchedAt`	datetime	When this data was last fetched (conversations only)

Available in:

GET /v1/inbox/conversations and GET /v1/inbox/conversations/{id} - on each participant
message.received webhook - on message.sender

Ice Breakers

Manage ice breaker prompts shown when users start a new Instagram DM conversation. Max 4 ice breakers, question max 80 characters.

See Account Settings for the GET/PUT/DELETE /v1/accounts/{accountId}/instagram-ice-breakers endpoints.

Comments

Feature	Supported
List comments on posts	✅
Post new top-level comment	❌ (reply-only)
Reply to comments	✅
Delete comments	✅
Like comments	❌ (deprecated since 2018)
Hide/unhide comments	✅

Webhooks

Subscribe to message.received to get notified when new DMs arrive. Messages are stored locally via webhooks.

Limitations

Reply-only comments - Cannot post new top-level comments, only replies to existing comments
No comment likes - Liking comments was deprecated in 2018

See Messages and Comments API Reference for endpoint details.

Connect Instagram Account - OAuth flow via Facebook Business
Create Post - Post creation and scheduling
Upload Media - Image and video uploads
Analytics - Post performance metrics
Messages and Comments - Inbox API
Account Settings - Ice breakers configuration