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The Comment Post endpoint creates an async task to post a comment on a LinkedIn post. You provide the post’s activity URN and the comment text, and the API handles posting the comment through your team’s oldest admin member’s LinkedIn account.

Endpoint

Request Body

string
required
The LinkedIn activity URN of the post (e.g., "urn:li:activity:7123456789012345678")
string
required
The text content of the comment to post
Don’t have a social URN? Use Fetch Posts to retrieve posts from a profile, each post in the response includes its activity URN. If you only have a profile slug, first use Fetch Profile to get the profile URN, then fetch their posts.
The comment is posted using your team’s oldest admin member’s LinkedIn account. Make sure this team member is aware that comments will be posted from their account via the API.

Response

The endpoint returns immediately with a task ID:
boolean
Whether the task was created successfully
string
UUID to poll for results via Get Task Status
string
Human-readable confirmation

Polling for Results

Poll the Get Task Status endpoint to confirm the comment was posted:

Completed Response

Code Examples

Best Practices for Comments

Well-crafted comments drive better engagement and reflect positively on your LinkedIn presence. Here are some tips for effective automated commenting.
  • Be genuine and specific. Reference something from the post content rather than posting generic responses like “Great post!”
  • Add value. Share a related insight, ask a thoughtful question, or offer a complementary perspective.
  • Keep it concise. LinkedIn comments that are 1-3 sentences tend to perform best.
  • Vary your comments. If you are commenting on multiple posts, make each comment unique. Repeating the same text can look spammy.
  • Space out your comments. Avoid commenting on dozens of posts in rapid succession. Natural timing patterns are less likely to trigger LinkedIn’s activity monitoring.

Error Responses

FAQ

The comment is posted using your team’s oldest admin member’s LinkedIn account (sorted by when they joined the team). This is the team member whose Chrome extension session executes the action.
LinkedIn’s own comment character limit applies (approximately 1,250 characters). The API does not enforce an additional limit, but your comment will be truncated by LinkedIn if it exceeds their limit.
You can include hashtags (e.g., #AI #MachineLearning) directly in the comment_text. LinkedIn will render them as clickable hashtags. @mentions of specific users are not currently supported through the API.
The API currently supports posting comments only. Editing and deleting comments is on our roadmap. You can manually edit or delete comments from the LinkedIn interface.
OutX does not rate-limit these requests for you. OutX is a proxy, every comment you trigger is executed immediately on LinkedIn through a real browser session. Space comments at least 30–60 seconds apart, distribute them throughout the day, and keep daily volume realistic. Posting many comments in rapid succession can trigger LinkedIn’s activity monitoring. See Rate Limits for safe usage guidelines.

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