The Instagram 24-hour messaging window, explained

The 24-hour window

Meta only lets you send a free-form DM within 24 hours of a contact's last message

to you. That clock (the "24-hour window") resets every time they message you again. Miss

it, and a plain promotional DM will be rejected.

The private-reply exception

There is exactly one compliant way to DM someone who never messaged you first: a

private reply to a comment they left. It's allowed once per comment, within

7 days of the comment. This is how a "comment a keyword" campaign legally starts a

conversation.

Why it matters for automation

Good automation enforces these rules before the send:

• Track each contact's last inbound message to know if the window is open.
• Route comment campaigns through private replies, respecting once-per-comment / 7 days.
• Never try to force a free-form DM outside the window: that's how accounts get flagged.

A concrete example

Someone comments "GUIDE" today. You have 7 days to send them a private reply with the

guide. Once they reply to your DM, the 24-hour window opens and you can continue the

conversation freely until it lapses.