Comment to DM, explained
How it works
When someone comments on your post, Instagram tells CommentDM within seconds. If the comment matches your keyword, CommentDM sends them a private reply: a DM linked to their comment.
Instagram's rules
One private reply per comment, within 7 days. After they reply or tap a button, you can send more messages for 24 hours. CommentDM follows these rules for you.
Why some DMs don't arrive
The person may have messages from businesses turned off, or another tool already replied to the comment. CommentDM's log tells you which.
Busy posts
Instagram allows about 750 private replies an hour per account. CommentDM stays safely below that, at about 600 an hour, and on a viral reel it queues the rest and sends them in order.