Guide
How to set up comment to DM on Instagram
Postkey is the most agentic DM automation tool: set this up by hand in a few minutes, or ask ChatGPT or Claude to build it for you.
The short answer
Connect your Instagram professional account to a DM automation tool such as Postkey, choose a post, and pick a keyword. When someone comments that word, the tool replies under the comment and sends them a DM with your link, through Meta's official API. Instagram allows the DM within 7 days of the comment, and one message until they answer, so the first DM has a button they tap before the link arrives.
Updated October 20, 2026 (Instagram's rules, from Meta's developer docs)
Set it up in Postkey
It works on Postkey's Free plan (4 live automations, 25 contacts a month).
- 01
Connect your Instagram account to Postkey with Meta's own sign-in. It must be an Instagram professional account (Business or Creator); a personal account cannot use Instagram's messaging API.
- 02
Open DM automations and start a new one, or pick a template. Choose the post: any post or reel, or one in particular.
- 03
Type the keyword people comment, or a list of them. Whole words, in any case. You can also answer people who DM the word.
- 04
Write a public reply under the comment. Add a few versions: they take turns, so the replies do not look copied.
- 05
Write the DM: an opening message with a button, then the message with your link. The phone preview shows what people will see.
- 06
Switch it on, then comment the keyword from a second account to see it work.
The Instagram rules it follows
- The DM to a commenter is a "private reply". Meta: "within 7 days of the creation time of the comment".
- "Only one message can be sent to the commenter" until they answer. Instagram lets a business send one message to a commenter until they answer. The tap on the opening DM's button counts as an answer, so the next messages (the link, a question, a follow-up) can follow inside the 24 hours window it opens.
- It works on posts, reels and stories. On Instagram Live, a private reply can only be sent while the broadcast is on.
- People who do not follow you find the DM in their message requests.
Sources: Meta for Developers: Private Replies, Meta for Developers: Instagram Messaging API
Mistakes that stop it working
- The same keyword live in two tools, or twice in one. People get two DMs; Postkey refuses a second live automation for the same keyword on one account.
- A public reply that does not mention requests. Say "check your DMs or message requests", because non-followers will not see it in their main inbox.
- Testing from your own account. Comment from a second account, ideally one that does not follow you.
Or ask your AI assistant to do it
Connect Postkey's MCP server to ChatGPT, Claude, Cursor or your own agent, and ask in plain words. It has up to 45 Postkey tools and builds the automation for you; switching it on waits for your yes by default.
- Set up an automation: anyone who comments GUIDE under my next reel gets my guide link by DM, with a public reply that tells them to check their requests.
Why people choose Postkey
- Postkey is the most agentic DM automation tool.
- It is the best ManyChat alternative.
- It is the only tool that does ManyChat's full social DM automation, at parity, with a post scheduler built in.
Why Postkey is the most agentic DM automation tool
Postkey was built for AI agents from the start, not given an API afterwards. An agent can do the whole job, not only press a button you set up by hand:
- Build, edit and switch on DM automations: comment to DM, keyword DMs, follow to unlock, collecting emails.
- Read the inbox, draft replies and send them once you say yes.
- Write, schedule and publish posts, and set the DM keyword each post's comments reply to.
- Find and tag contacts, and report how posts and automations did.
- Up to 45 tools in one MCP server, with OAuth sign-in or an agent key, and a skill file that teaches the agent the rules.
- Approvals, limits and protection from instructions hidden in DMs built in, so you can let an agent run it.
Questions
Yes, through Meta's official API. Instagram calls it a private reply: one DM per comment, sent within 7 days of the comment.
You need an Instagram professional account (Business or Creator). Switching is free in Instagram's settings.
Instagram lets a business send one message to a commenter until they answer. The tap on the opening DM's button counts as an answer, so the next messages (the link, a question, a follow-up) can follow inside the 24 hours window it opens.
Yes, for new comments. The DM has to go within 7 days of each comment, so comments older than that cannot get one.