Instagram private replies API: the rules, limits and examples

What is the Instagram private replies API?

Private replies are the part of Meta's API that turns a public comment into a private conversation. Meta's page describes it as the way "to programmatically send a private reply to a person who commented on your app user's Instagram professional post, reel, story, Live, or ad post." Every comment-to-DM tool on the official API, including ReplyRep, is built on it.

Meta documents private replies in two places, one for each way of connecting an Instagram account: the Instagram Platform docs (last updated June 30, 2026) and the Instagram Messaging docs on the Messenger Platform (last updated July 2, 2026). The wording differs slightly. The rules are the same. We found no 2026 change to the private reply rules (one message, 7 days, 750 an hour) in either Meta changelog.

How does a private reply work?

1. 1

   Someone comments

   A person comments on a post, reel, story, Live or ad on an Instagram professional account. For comment-to-DM, the comment usually contains a keyword like GUIDE or LINK.

2. 2

   The app sends one private reply

   The app sends a single message to that person, tied to their comment. It must go within 7 days of the comment, or during the broadcast for Live.

3. 3

   The reply lands

   In the person's Inbox if they follow the account, or in their Requests folder if they do not. Meta adds a link to the commented post.

4. 4

   If they reply, the conversation opens

   Their response opens the standard messaging window. The app can keep talking for 24 hours from their latest message.

5. 5

   If they do not reply, that is the end

   No second message can be sent through the API off the back of that comment.

What are the private reply rules and limits?

Your app can send this private reply within 7 days of the creation time of the comment, excepting Instagram Live, where replies can only be sent during the live broadcast.

One detail trips up a lot of people. Meta's general Messenger Platform docs list a comment among the actions that open a 24-hour window. For Instagram comments, the Private Replies pages are stricter and more specific: one message, then nothing until the person responds. Follow the stricter rule. Our guide to the Instagram 24-hour messaging window walks through the difference.

Who can use private replies?

• Professional accounts only. Meta says app users "must have an Instagram professional account", which can be a business or a creator account.
• No Facebook Page needed with Instagram Login. Meta's overview says the Instagram API with Instagram Login "serves Instagram professional accounts without requiring a linked Facebook Page." The Facebook Login setup does need a connected Page.
• Apps serving other people's accounts need Advanced Access. Meta says this "requires App Review and Business Verification."
• A human must be reachable. "Apps that use the Instagram Messaging APIs must have an escalation path to a human agent."

Private reply vs public reply vs DM: what is the difference?

Most good comment-to-DM setups use the first two together: a public reply under the comment ("Sent, check your DMs") and the private reply with the link. The comment-to-DM glossary entry and private reply definition cover the terms.

How do you write the one message?

Because Meta allows one private reply per comment, the message has two jobs: deliver what you promised, and give the person a reason to reply so the conversation can continue. A teaser that says "reply YES for the link" spends your one message on nothing.

• Link in the first message. If they never reply, this is all they get.
• Say where it came from. "You asked for this under my reel" reads as expected, especially in Requests.
• End with an easy question. A reply opens the 24-hour window for the next message.
• Keep the promise exact. Meta's spam policy names "failing to deliver promised experiences".

What does this mean for a viral post?

The 750 per hour limit is per account, across all posts and reels. That is 18,000 a day at full speed. A reel that pulls 3,000 keyword comments in an hour needs about four hours to answer everyone. That is slower than the usual few seconds, but far inside Meta's 7-day deadline, as long as the tool keeps the overflow instead of dropping it. Our full breakdown is in Instagram DM limits.

How does ReplyRep use private replies?

• [Comment-to-DM](/features/instagram-comment-to-dm) on every plan. Someone comments your keyword on a post, reel or ad, and the private reply goes out about three seconds later. Comments without the keyword are left alone.
• A public reply alongside it. Comment Auto Reply (Lite and up) answers under the comment, worded differently each time.
• Overflow waits its turn. The Excess DM Queue (Lite and up) holds anything over Meta's limit in order, and SendBack DMs (Lite and up) go back for interactions that were skipped or delayed.
• Official API, no password. ReplyRep is a Meta Business Partner on Meta's official Instagram API, and you connect through Meta's login.

ReplyRep automates comments on posts, reels, stories and ads, story replies, story mentions and DMs. It does not offer Instagram Live comment automation.

Common myths about private replies

• Myth: A comment opens a 24-hour window. For Instagram comments, it allows one private reply. More only after the person responds.
• Myth: You must reply within 24 hours of the comment. Meta gives 7 days for posts, reels and ads. Live is the exception.
• Myth: Private replies only work on posts. Meta lists posts, reels, stories, Live and ad posts.
• Myth: Private replies always land in the inbox. Non-followers get them in Requests.
• Myth: You can reply privately to old comments in bulk. Only comments from the last 7 days can get a private reply.