How do you publish a post to Instagram with the API?

What you need first

From Meta’s Content Publishing guide and its Instagram Platform overview, read on 11 October 2026:

• A professional account. The app’s users must have an Instagram professional account, which can be a business or a creator account.
• A login configuration. There are two, and the choice sets the host, the token and the permissions.
• An access level. Standard Access is the default and is enough if your app serves only your own account or accounts you manage. Advanced Access, needed for accounts you don’t own or manage, requires App Review and Business Verification.
• Media on a public server. Meta says it fetches the file with cURL, so the file must be on a publicly accessible server when you make the attempt.
• Page Publishing Authorization. If the Facebook Page connected to the account requires it, the API can’t publish until it is completed. Meta says there is no way for you to tell whether a Page requires it, and recommends advising users to complete it ahead.

If the account’s Page role came through a Business Manager, the Facebook Login route also needs ads_management and ads_read.

The three calls

1. Create a container. POST /<IG_ID>/media with image_url or video_url, a caption, and media_type set to REELS or STORIES where it applies. A carousel is media_type=CAROUSEL with children, up to 10 container IDs that were each created with is_carousel_item=true. The response is {"id": "<IG_CONTAINER_ID>"}.
2. Check the container. GET /<IG_CONTAINER_ID>?fields=status_code returns EXPIRED, ERROR, FINISHED, IN_PROGRESS or PUBLISHED. Video uploads are asynchronous, so a container ID doesn’t mean the video arrived. Meta suggests asking once a minute, for no more than 5 minutes.
3. Publish. POST /<IG_ID>/media_publish with creation_id set to the container ID. The response is the media ID.

A container that isn’t published within 24 hours expires. For a large video from an unreliable connection, upload_type=resumable returns a container and an upload address on rupload.facebook.com; the guide says that option is for apps that have implemented Facebook Login for Business.

The limits

From the guide and the IG User media reference:

The free video checker tests a reel’s length, size and shape against these limits in your browser, without uploading it. Stories can mention users, but publishing link, poll and location stickers isn’t supported. Filters aren’t supported either, and alt text is for image posts, not reels or stories.

Where Meta’s pages disagree

• 100 posts or 50. The rate-limit section of the guide says 100 API-published posts in 24 hours. The carousel section of the same page says accounts are limited to 50 published posts in 24 hours. Meta says carousels count as one post and recommends that your app enforce the limit itself.
• 30 hashtags or 5. The media reference allows 30 hashtags in a caption. Instagram’s Help Center says up to 5 on a post, and that a comment with more than 5 won’t post. We have not tested what the API does with a sixth. The hashtag limit answer has the detail.
• Shopping tags. The guide lists shopping tags as not supported. The media reference documents product_tags, and the overview marks product tagging as supported on the Facebook Login route only.

What the API doesn’t do

The calls above have no field for a time: a post is published when you call media_publish. The guide itself says apps that let people schedule posts should enforce the publishing limit, which is how a scheduling tool works: it keeps the post and runs the three calls at the chosen time. Scheduling Instagram Reels covers Instagram’s own schedulers.

Publishing to Instagram with Mellow Hub

Hub reaches Instagram through its publishing provider, which holds the app approvals, so a person using Hub registers no Meta app and applies for no access level. A professional (Business or Creator) Instagram account. A personal account cannot publish through any API. A post takes a caption of up to 2,200 characters and 1 to 10 items. Stories take exactly one item. Reels take one video. Hub can connect an account through Instagram login or Facebook login, which are Meta’s two configurations above. It checks the caption and media against the network’s rules before anything is sent. The REST calls are in schedule social media posts with a REST API.

The first 3 posts are free, however many networks each one goes to, and need no card. After that Hub is paid: plans start at $19 a month (Solo), after a 7-day trial with a card on file that costs nothing if you cancel before it ends, and a monthly plan's first month is 20% off. Publishing is unlimited on every plan, under a fair-use ceiling that stops automated floods (900 publications a month on Solo), where one publication is one post on one account, so a post sent to five networks counts as five toward it. There are no automatic overage charges.