LinkedIn Upload API

This section details how to upload text posts, photos, multi-image posts, videos, and document carousels to LinkedIn personal profiles and company pages.

Base URL

https://api.multi-upload-tool.com/api/v1

Authentication

All requests require an API Token in the header: x-api-key: YOUR_API_TOKEN

Personal Profiles & Company Pages

LinkedIn personal profiles and company pages are both connected as separate accounts. When you connect a LinkedIn company page, it appears as its own account with its own accountId. You simply post to that account directly — there is no need for a separate targetPageId parameter.

Important: Title vs Description

On LinkedIn, the description field is what appears as the body text of the post. This is the main content your audience sees.

The title field is not published to LinkedIn. It is only used internally within the Multi Upload Tool UI (e.g. in the upload history, pools, and scheduling views) to help you identify your posts. If you want text to appear on LinkedIn, put it in description.

Text Formatting

The API automatically converts Markdown-style formatting to Unicode characters that render as bold and italic on LinkedIn.

This conversion happens automatically. You simply write your description using standard Markdown bold/italic syntax.

Example

**Big News!** We're launching *something amazing* this week.

Check out our ***brand new product*** now.

Notes

• Accented characters (e, a, etc.) are not converted as there are no Unicode bold/italic equivalents for diacritics.
• Emojis, punctuation, and special characters pass through unchanged.
• Bullet points (* item) are not mistakenly converted to italic.
• Hashtags (#topic) and mentions work normally alongside formatting.

Requirements

LinkedIn Photo Requirements

• File Format: JPEG, PNG, GIF, WebP
• Max File Size: 10 MB

LinkedIn Multi-Image Requirements

• Image Count: 2 to 20 images per post
• File Format / Size: same as single photo (JPEG, PNG, GIF, WebP; 10 MB each)

LinkedIn Video Requirements

• File Format: MP4 (recommended), MOV, AVI, MKV
• Max File Size: 500 MB
• Duration: 3 seconds to 15 minutes (recommended)

LinkedIn Document (Carousel) Requirements

• File Format: PDF, DOC, DOCX, PPT, PPTX
• Max File Size: 100 MB

Validation & Limits

This table documents all validation limits enforced by the Multi Upload Tool API for LinkedIn uploads. These limits are based on our code implementation and LinkedIn’s official API documentation.

Source: LinkedIn Content Consumption API 

Upload Text Post

Create a text-only post on LinkedIn.

Endpoint

POST /upload

Content-Type

multipart/form-data

Parameters

Query Parameters

Body Parameters

Example Request

curl --location 'https://api.multi-upload-tool.com/api/v1/upload' \
--header 'x-api-key: YOUR_API_KEY' \
--form 'accountId="12345"' \
--form 'description="**Exciting news!** We just launched *something new*."' \
--form 'visibility="PUBLIC"'

Upload Photo

Upload a single photo to LinkedIn.

Endpoint

POST /upload

Content-Type

multipart/form-data

Parameters

Query Parameters

Body Parameters

Example Request

curl --location 'https://api.multi-upload-tool.com/api/v1/upload' \
--header 'x-api-key: YOUR_API_KEY' \
--form 'accountId="12345"' \
--form 'photo=@"/path/to/image.jpg"' \
--form 'description="Check out our new office! **We are hiring.**"' \
--form 'visibility="PUBLIC"'

Upload Multi-Image Post

Publish a multi-image post by sending the photo field multiple times. The images appear as a swipeable gallery on LinkedIn.

Endpoint

POST /upload

Content-Type

multipart/form-data

Parameters

Query Parameters

Body Parameters

Example Request

curl --location 'https://api.multi-upload-tool.com/api/v1/upload' \
--header 'x-api-key: YOUR_API_KEY' \
--form 'accountId="12345"' \
--form 'photo=@"/path/to/image1.jpg"' \
--form 'photo=@"/path/to/image2.jpg"' \
--form 'photo=@"/path/to/image3.jpg"' \
--form 'description="Highlights from our team offsite"' \
--form 'visibility="PUBLIC"'

Notes

• A multi-image post requires 2 to 20 images. A single photo is published as a normal single-image post.
• Each image must meet the LinkedIn photo requirements (JPEG, PNG, GIF, WebP; max 10 MB each).

Upload Video

Upload a video to LinkedIn.

Endpoint

POST /upload

Content-Type

multipart/form-data

Parameters

Query Parameters

Body Parameters

Example Request

curl --location 'https://api.multi-upload-tool.com/api/v1/upload' \
--header 'x-api-key: YOUR_API_KEY' \
--form 'accountId="12345"' \
--form 'video=@"/path/to/video.mp4"' \
--form 'description="Watch our latest product demo"' \
--form 'visibility="PUBLIC"'

Upload Document (Carousel)

Upload a PDF or document to LinkedIn as a carousel post.

Endpoint

POST /upload

Content-Type

multipart/form-data

Parameters

Query Parameters

Body Parameters

Example Request

curl --location 'https://api.multi-upload-tool.com/api/v1/upload' \
--header 'x-api-key: YOUR_API_KEY' \
--form 'accountId="12345"' \
--form 'photo=@"/path/to/slides.pdf"' \
--form 'description="**5 tips** to *boost your productivity* this quarter"' \
--form 'media_type="DOCUMENT"' \
--form 'visibility="PUBLIC"'