Post to Instagram with the 1Post API

Connect Instagram first

1. 01

   Open Accounts in 1Post and choose Connect.

2. 02

   Pick Instagram.

3. 03

   Sign in with Instagram and approve access for the Business or Creator account you want to post to.

4. 04

   Choose the Business or Creator account in 1Post. It is ready to pick in the composer.

Then GET /v1/accounts returns the id of the Instagram account to use in the request.

Send a post to Instagram

Instagram refuses a post without media, so upload the file first and put its id in media_ids (POST /v1/media/uploads, or POST /v1/media to fetch a public address). Then schedule the post.

curl https://api.get1post.com/v1/posts \
  -H "Authorization: Bearer $ONEPOST_API_KEY" \
  -H "Idempotency-Key: instagram-first-post" \
  -d '{"accounts":["ACCOUNT_ID"],"parts":[{"text":"New batch just out of the oven.","media_ids":["MEDIA_ID"]}],"schedule_at":"2026-11-02T15:00:00Z"}'

The reply is 202 with the post (status scheduled) and one destination for Instagram, which moves from queued to published or failed.

What you can send to Instagram

• Image
• Carousel
• Reel
• Story
• Trial Reel
• First comment
• Collaborators (up to 3)
• Cover image and alt text

What Instagram publishes

• JPEG is the only image format supported, and shopping tags and filters are not supported when publishing through the API.
• A carousel can hold up to 20 images, videos or a mix, and counts as one post against the publishing limit.
• The publishing limit is stated as 100 posts in a 24-hour moving period in one place and as 50 in another on the same page.

Instagram rules the request is checked against

The same table with sources is on the Instagram specs page.

Instagram options in the request

• First comment: add first_comment with text (up to 2,200 characters) to an account object, and delay_min if it should wait.
• Media is required: Instagram refuses a post without it. Upload the file first (POST /v1/media/uploads, or POST /v1/media to fetch a public address) and list its id in the media_ids of a part.

Check the post before it is queued

Add "dry_run": true to test a post: nothing is kept, a valid one answers 200 and a broken one answers 422 naming the rule.

{
  "error": {
    "code": "invalid_for_platform",
    "message": "instagram refuses this post: Instagram counts 2,232 of 2,200 characters in part 1. (text_too_long).",
    "fix": "Fix the rule named in the message and send the post again.",
    "retryable": false,
    "request_id": "REQUEST_ID"
  }
}

An assistant connected to the MCP server sends the same fields to create_post; set one up.