Short answer: when someone comments your keyword, Instagram lets you send that person one private reply to their comment, within 7 days. That is the mechanism behind every “comment ITEM1 and I’ll DM you the link” post you have seen. It is an official feature, not a loophole.
Why creators use it
Sending people to a link in bio loses most of them. A keyword works because the person is already interested enough to type it, they get what they asked for in seconds, and you have started a real conversation instead of a click. It also does something the algorithm likes: your post collects a burst of comments quickly, which is one of the clearest signals that a post is worth showing to more people.
How it actually works
- You post something and ask people to comment a specific word.
- Someone comments it. Instagram notifies the tool through a webhook, within seconds.
- The tool checks the comment against your keyword.
- It sends that person a private reply — a DM attached to their comment.
- Optionally it also replies publicly, so everyone else can see the offer is real.
The important detail is the private reply. Instagram does not let apps message people out of the blue. But when someone comments on your post, it opens a specific, permitted window to reply to them privately: one reply per comment, within 7 days. If they write back, a normal 24-hour conversation window opens and you can keep talking.
The DM version of the same idea
You can run the same trigger on direct messages: “DM me ITEM1 and I’ll send the template.” This is even simpler, because their message to you opens Instagram’s standard 24-hour reply window — there is no per-comment limit to work within. It works well in Stories, where a keyword sticker or a “send me a message” prompt is natural.
What to use it for
- Selling a product — “comment DRESS for the link” on an outfit Reel.
- Sharing a resource — a prompt, a recipe, a checklist, a discount code.
- Booking — send your calendar link to people who ask for it.
- Growing a list — send a signup link to people who already raised a hand.
Getting it right
- Pick a distinctive keyword. “LINK” will fire on half your comments. “ITEM1” or “BEACHVIDEO” will not. Good tools match on whole words, so ITEM1 does not trigger on ITEM10.
- Say the keyword out loud and put it on screen. Most people watch Reels on mute and never open the caption.
- Deliver something genuinely worth asking for. A weak payoff trains people to ignore your next one.
- Reply to the humans too. Automation starts the conversation; it should not be the whole of it.
- Consider limiting it to followers. Making the offer a reason to follow turns one post into new followers rather than just clicks.
What it will not do
It cannot message people who have not interacted with you. It cannot send more than one automatic reply per comment. And it will not rescue a post nobody sees — if reach is your problem, fix the hook and watch time first, because a keyword only converts the attention you already have.
Setting it up in Valarcha
Valarcha’s Automations section runs both triggers — comments and DMs — through Instagram’s official API. You set the keyword, the message people receive, an optional public reply, and whether it should only go to followers. Every send is logged so you can see exactly who asked and what went out. Because it sits alongside your analytics, you can also see which posts actually drove the keyword — not just how many DMs went out.