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LinkedIn API: Posting Reference

LinkedIn appears as two independent channels: one for a personal profile and one for a company page. A single workspace can connect both at the same time and post to each separately.

Channel ID	Target
linkedin	Personal profile (the individual who connected the account)
linkedin_page	Company page (the organization whose page was selected during OAuth)

Both channels share a single LinkedIn OAuth token under the hood. Reconnecting either refreshes credentials for both.

Supported content types

Type	linkedin (Profile)	linkedin_page (Page)
Feed post	✅	✅
Story	-	-
Reel	-	-

LinkedIn does not support stories or reels through its API. Only feed posts work.

Minimal example

Posting to a personal profile:

Code
curl -X POST https://api.omnisocials.com/v1/posts/create \
  -H "Authorization: Bearer $OMNISOCIALS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": { "default": "Excited to share our latest update." },
    "accounts": ["your-linkedin-profile-account-id"]
  }'

Posting to a company page:

Code
curl -X POST https://api.omnisocials.com/v1/posts/create \
  -H "Authorization: Bearer $OMNISOCIALS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": { "default": "Company announcement." },
    "accounts": ["your-linkedin-page-account-id"]
  }'

Posting the same content to both simultaneously: include both account IDs in the accounts array. OmniSocials publishes to each independently.

Code
curl -X POST https://api.omnisocials.com/v1/posts/create \
  -H "Authorization: Bearer $OMNISOCIALS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": {
      "default": "Same content on both",
      "linkedin": "Personal voice for the profile",
      "linkedin_page": "Official company announcement"
    },
    "accounts": [
      "your-linkedin-profile-account-id",
      "your-linkedin-page-account-id"
    ]
  }'

Platform-specific options

Set a first comment under the channel's own key: linkedin for the profile, linkedin_page for the company page:

Field	Type	Description
linkedin.first_comment	string	Text auto-posted as the first comment on the profile post right after it publishes (max 1250 characters). Common for "link in first comment" to avoid the in-caption link reach penalty.
linkedin_page.first_comment	string	Same, for the company page post (max 1250 characters).
linkedin_poll	object	Non-sponsored poll; see Polls below.

Aside from the optional first comment and poll, LinkedIn has no required option fields; the default create-post body works for both channels.

Polls

LinkedIn's Poll API lets you post a non-sponsored poll: a question with 2-4 answer options and a duration. Pass a top-level linkedin_poll object keyed by channel: linkedin (personal profile) and linkedin_page (company page) each carry their own independent poll, or none. content is still the post's caption, shown above the poll.

Code
curl -X POST https://api.omnisocials.com/v1/posts/create \
  -H "Authorization: Bearer $OMNISOCIALS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": { "default": "What should we build next?" },
    "accounts": ["your-linkedin-account-id"],
    "linkedin_poll": {
      "linkedin": {
        "question": "What should we build next?",
        "options": ["Mobile app", "Public API", "More integrations"],
        "duration": "SEVEN_DAYS"
      }
    }
  }'

Field	Type	Description
linkedin_poll.linkedin	object | null	Poll for the personal profile post. Omit or null = not a poll.
linkedin_poll.linkedin_page	object | null	Poll for the company page post. Omit or null = not a poll.

Each poll object:

Field	Type	Description
question	string	The poll question (max 140 characters).
options	string[]	2-4 answer options (max 30 characters each).
duration	string	ONE_DAY | THREE_DAYS | SEVEN_DAYS | FOURTEEN_DAYS.

A poll is mutually exclusive with media and a link share on that channel's post; if the request also carries media_urls/media_ids or a link share, the poll silently takes priority at publish time (same precedence LinkedIn's own media-vs-article rule uses), so don't send both.

Post a different poll to the profile and the page in one call by setting both keys:

Code
{
  "linkedin_poll": {
    "linkedin": { "question": "What should WE build?", "options": ["A", "B"], "duration": "SEVEN_DAYS" },
    "linkedin_page": { "question": "What should our COMPANY build?", "options": ["A", "B", "C"], "duration": "FOURTEEN_DAYS" }
  }
}

linkedin_poll is also accepted on PATCH /posts/{id}; it replaces the whole object wholesale (both channels), so send the full desired state, not just the channel you're changing. GET /posts/{id} echoes it back. Set a channel's key to null (or send linkedin_poll: null) to clear that channel's poll (or every poll) and revert to a normal post.

Media requirements

Media	Requirement
Image	JPEG or PNG, max 10 MB
Video	MP4 or MOV, up to 10 minutes, max 5 GB

LinkedIn supports text-only posts, a single image, a multi-image carousel, or video. Mixing image and video in the same post is not supported.

Posting 2 or more images publishes LinkedIn's native document carousel: OmniSocials renders the images into a single PDF and uploads it as a document, the same swipeable format LinkedIn's own composer produces, instead of a plain multi-image gallery. There's no image-count limit enforced on our side.

Prefer the plain multi-image gallery for a specific post? Set carousel_as_images: true on the linkedin and/or linkedin_page option object (the same objects that carry first_comment). The flag is independent per channel and is ignored for text-only posts, single images, videos, and polls:

Code
{
  "content": { "default": "Five looks from the spring shoot" },
  "accounts": ["your-linkedin-account-id"],
  "media_urls": ["https://example.com/1.jpg", "https://example.com/2.jpg"],
  "linkedin": { "carousel_as_images": true }
}

On PATCH /posts/{id} the flag merges per channel: true sets it, false (or null) reverts that channel to the default document carousel, and omitting it keeps the current value. GET /posts/{id} echoes it back inside each channel's option object.

Alt text

Pass an accessibility description per media item by using an object entry instead of a bare string (works in media_urls and media_ids). It is sent as LinkedIn's altText on images: both single-image posts and multi-image galleries, where each image carries its own description. Video and documents don't support alt text (a LinkedIn limitation):

Code
{
  "content": { "default": "Team offsite highlights" },
  "accounts": ["your-linkedin-account-id"],
  "media_urls": [
    { "url": "https://example.com/team.jpg", "alt": "Six people around a whiteboard covered in sticky notes" }
  ]
}

The same alt also delivers to Mastodon, Bluesky, X, Pinterest, and Instagram (images), so one description covers a cross-platform post.

Mentions

LinkedIn mentions must reference either another LinkedIn member or a company, using the URN format the LinkedIn API expects. OmniSocials exposes mention handling through the mentions field on the post body. See the API reference for the full shape.

Limitations

• Stories and reels are not available through LinkedIn's public API
• LinkedIn enforces a 3,000 character limit per post. Posts exceeding this are rejected.
• Posting to company pages requires the connecting user to be an admin of the page
• The personal profile channel (linkedin) requires the Community Management API product on LinkedIn Developer, which is automatically configured for OmniSocials customers