Broadcast DM
Why it matters for creators
Most DM automation answers one person at a time, triggered by something they did. A broadcast inverts that: you decide the moment, and one message goes to everyone the account is currently allowed to message.
The constraint is the whole story. Instagram does not let a business open a conversation, so a broadcast can only continue conversations that already exist, with the people whose messaging window is still open. That means everyone who sent you a DM, replied to one of your stories, or tapped a button in one of your automations in the last day. A follower who has never written to you is not reachable, and no tool on the official API can reach them.
This is why the honest question to ask a tool is not whether it broadcasts, but who its number counts. A count built from a saved contact list will include people who went quiet weeks ago, and every one of those sends is refused at the moment it goes out. A count built from the conversation ledger tells you who you can actually reach right now, which is usually a far smaller and far more useful number.
A broadcast DM is also not an Instagram broadcast channel, which is a one-way feed followers opt into and cannot reply to. The two share a word and almost nothing else.