To send an automatic DM when someone comments on your Instagram post, use a tool that supports Meta’s private replies: a rule watches new comments for a keyword such as INFO, and each person who comments it gets one direct message from your account. Meta allows one private DM per comment, sent within 7 days of the comment, and the DM includes a link to the post they commented on. In VivaDialog this is the Also send a DM? step of a rule.
What Meta allows
Private replies are part of Meta’s official messaging API, and Meta sets the limits. From Meta’s Instagram private replies documentation:
- One message per comment. Only one private reply can be sent to the person who commented.
- Within 7 days of when the comment was made. On Instagram Live, only during the broadcast.
- Where it lands. The DM appears in the person’s Inbox if they follow your account, and in their message Requests if they do not.
- A link to the post is included with the message.
- Follow-ups need a reply first. You can only send more messages after the person answers, and then within 24 hours of their answer.
Facebook Pages work the same way: one private reply per comment, within 7 days, and the conversation can continue only after the person responds (Meta’s Messenger private replies documentation).
Threads has no API for direct messages, so no tool can send DMs to people who comment on Threads.
Set it up in VivaDialog
You need a connected Instagram account, and you need to be an owner or admin of the workspace.
- Open Automation and click New rule.
- Pick Comment INFO, get the details by DM. It replies publicly with a short note and sends the details by DM. You can change every part of it.
- Under When should this run?, keep New comment.
- Under Which messages?, type the words people should comment, separated by commas. Capital letters do not matter.
- Under How should it reply?, keep the short public reply, or choose Don’t reply to send only the DM.
- Under Also send a DM?, tick Send a private DM to the person who commented and write the DM. Replace the text in square brackets with your own link or offer; the rule cannot be saved while a placeholder is left.
- Use Test it first with a comment like the one you expect, then click Save rule.
The DM text is fixed: everyone who matches gets the same message. If you want the public reply to answer questions in more detail, choose Answer with AI for the reply and keep the DM for the link.
Or send the DM by hand
You do not need a rule for a one-off. In the VivaDialog inbox, open the comment, click Reply by DM, write your message, and click Send DM. The same Meta limits apply: one DM per comment, within 7 days of the comment. If a rule already sent one, the inbox will not let you send a second.
Writing a DM people answer
Because you can only send more messages after the person replies, the first DM has to do the work on its own.
- Give them what they asked for. If the post said “comment INFO for the price list”, put the price list or its link in the DM.
- Keep it short. One or two sentences and one link.
- Invite a reply. End with a question they can answer, such as which size or date they need. Their answer opens the 24-hour window for you to continue the conversation.
- Say who you are if your account name does not make it obvious.
Tell people on the post what to comment and that the details arrive by DM. Without that, a DM from an account they do not follow lands in Requests and looks unexpected.
What happens next
When the person answers the DM, the conversation arrives in your VivaDialog inbox with your other DMs, and you or another rule can reply. A DM sent for a comment counts as the same conversation as that comment in your monthly quota, not as a second one.
If they answer and then go quiet, a rule can send one reminder later in the same conversation, from 1 minute to 23 hours after their message. The reminder is cancelled if they write again, if your team has already replied, or if Meta’s 24-hour window has closed. The “Price question, with a reminder 2 hours later” template shows how it works.
A few limits apply on top of Meta’s:
- VivaDialog sends at most one DM per comment, even when several rules match.
- Rules never answer comments older than 24 hours, so DMs go out well inside Meta’s 7-day limit.
- Comments written by your own account never trigger a rule.
Before you switch it on
Only DM people who asked for something by commenting, and send them what they asked for. Unrequested DMs are the kind of messages Instagram says it limits. Is Instagram comment automation safe? covers what gets accounts restricted, and how to auto-reply to Instagram comments walks through every field of a rule.