A private reply is a direct message you are allowed to send to someone in response to their public comment on your Facebook or Instagram content. Meta permits exactly one private reply per comment, and only within a limited window after the comment is posted — it is a way to take a public conversation private without cold-messaging anyone who has not engaged first.
For advertisers, private replies are a natural next step after a buyer-intent comment. When someone comments "is this still available?" on your ad, a public reply works, but a private reply lets you share order details, a discount link, or sizing help one-to-one — without broadcasting it under the ad for competitors and spammers to see.
ROAS Shield will draft private replies as part of ad comment moderation once Meta approves the required pages_messaging permission — that's not live yet. When it ships, you'll stay in full control: every draft will require human approval before it sends, with auto-send never available for DMs. (Public comment replies are live today and can optionally auto-send once you turn it on, under strict confidence and safety conditions. Regulated industries are forced to draft-only regardless of settings.)
Private replies are deliberately scoped: once available, ROAS Shield will use comment-driven private replies, not a full Messenger inbox or broadcast messaging, which keeps the feature inside Meta's policies and our App Review scope. See the FAQ for the full picture on replies and DMs.