Can I post to LinkedIn through the API without partner approval?

Or skip the LinkedIn app entirely

The OpenTweet LinkedIn app uses the self-serve Share on LinkedIn product, so you do not need one of your own. Go to Settings > Accounts > Connect LinkedIn, sign in with LinkedIn and approve. There is no developer app to register, no API key to issue and no partner application to file.

After that, LinkedIn is one value in the platforms array of the same endpoint that posts to X and Bluesky.

curl -X POST https://opentweet.io/api/v1/posts \
  -H "Authorization: Bearer ot_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "What we learned moving our job queue to Postgres.",
    "platforms": ["linkedin"],
    "publish_now": true
  }'

The outcome comes back per network. A LinkedIn result carries the post URN and a link to it in the feed.

{
  "results": [
    {
      "platform": "linkedin",
      "status": "published",
      "post_id": "urn:li:share:7300000000000000000",
      "url": "https://www.linkedin.com/feed/update/urn:li:share:7300000000000000000/"
    }
  ]
}

Swap publish_now for scheduled_date and the OpenTweet queue handles the timing the LinkedIn API does not. Pass ["x", "bluesky", "linkedin"] to send the same post to all three. GET /api/v1/cross-posting reports the LinkedIn limits alongside the others, with max_text_length 3000 and text_unit "codeunit".