Can you auto-post from Instagram to TikTok?

What Instagram shares to by itself

Read on 11 October 2026.

• Threads. In the Instagram app, Also share on… before you post lets you switch on your Threads account and choose Always share posts or Share this post (Instagram Help).
• Facebook. Meta’s Accounts Center page lists sharing posts, stories or reels across Instagram and Facebook, and from either to Threads, and WhatsApp Status to Facebook or Instagram Stories.
• Older options. Instagram’s pages on sharing to other networks and on sharing an existing post name Facebook, Twitter, Tumblr, Mixi and Weibo. They still say Twitter, and we haven’t checked which of these options your app still shows.

TikTok is on none of these pages.

What TikTok’s page offers

TikTok’s page on making a post has you tap Upload to add a video from your device, then add a description, hashtags, tags, a location, a link and privacy settings, and tap Post or Drafts. None of those settings sends the post anywhere else, and the page describes no way to pull in a post from Instagram. We found no TikTok page that does.

The manual route, and what the file carries

Instagram’s page on who can download your reels says anyone can download a public account’s Reels unless the owner turns it off, and that no one can download from a private account. A downloaded Reel includes an Instagram watermark, the username and audio attribution, and downloaded Reels aren’t allowed for commercial purposes. The cleaner file is the one you made before Instagram saw it. How to post a TikTok on Instagram walks through the watermark question in the other direction and what each app says about it.

Why an automatic relay isn’t a settled thing

An app that posts to TikTok for a creator does it through the Content Posting API, and TikTok’s content sharing guidelines, updated 4 August 2026, set the terms:

• The app must start sending content only after the user has expressly consented to the upload, and should show a preview and let the user edit the title and hashtags.
• The user picks the privacy status, with no default value, and turns on the comment, duet and stitch settings themselves.
• The app should help authentic creators post original content. TikTok lists as not acceptable an app that copies arbitrary content from other platforms, and a utility tool that uploads only to accounts you or your team manage.
• An app TikTok hasn’t audited can post only privately.

The page doesn’t say how these apply to a rule such as “send everything I post on Instagram to TikTok”, and we haven’t asked TikTok. The broader picture is in is social media automation allowed.

Posting to both at once with Mellow Hub

Hub doesn’t fetch anything from Instagram or TikTok. You give it the file once and choose both networks, each with its own caption: Hub checks up to 2,200 characters for Instagram and 2,200 for TikTok. For TikTok it can publish directly or send the video to your TikTok inbox as a draft. The post goes out as one request, at once or at a set time, and each network succeeds or fails on its own.

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.