Automate what happens when someone comments
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A comment on your post or reel starts a flow: a reply under it, the one private DM Meta allows, a hide, or a different way for each person.
- Meta's official API, no password, nothing installed
- Unlimited contacts on every plan
- AI replies in your customer's language
- From $29 a month
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Every choice on the start, in plain words
The settings panel opens when you click the start on the canvas. These are its words.
Where it listens
The first choice on the start is which posts count.
- Any post or adEvery post, reel and ad
Comments anywhere on the account or page start the flow, ads included.
- Posts and reels onlyLeave the ads out
Only organic posts and reels count; comments on ads do not start this flow.
- Pick postsChosen posts
Pick the posts it runs on. Older ones are found by searching captions or pasting the post’s link.
Search captions or paste a post link.
- Your next postThe post you publish next
The start waits for your next post and binds itself to it; comments on it start the flow from the moment it is up.
Bound to your newest post. Comments on it start this flow.
Which comments count
Keywords, exact words, or every comment.
- Has a keywordAny of your words, anywhere in the comment
Up to 50 keywords, each up to 80 characters. Capitals and accents do not matter, and a keyword must start a word, so “hi” is not found in “this”.
A keyword matches its common endings (price finds prices and priced) but never a longer word (link does not match linkedin).
- Is exactlyThe whole comment is one of your words
For one-word campaigns where “LINK” should count and a sentence that mentions it should not. A leading ¿ or ¡ and trailing punctuation are ignored.
- Any commentEvery comment
No keyword at all: every comment on the chosen posts starts the flow.
- Every language
Keywords work in scripts without spaces (Chinese, Japanese, Thai) and with Arabic prefixes attached, so السعر is found in بالسعر.
How often
Set once on the start; it holds for every step after it.
- How often per personEvery time, once ever, once per post, once a day or once a week
“Once per post” is the comment start’s own choice: the same person gets the DM again on your next post, never twice on one.
Someone who already went through it is skipped quietly.
- Change startSwitch the start later
The steps stay. Steps that only fit the old start show as things to fix.
From the comment to the chat
The canvas knows which steps fit after a comment and which need the chat open first.
A comment flow begins on the comment, so its first steps are the ones Meta allows there: a public reply under it, a hide, and the one private reply. The chat opens when they tap its button or answer it; then messages, questions and the follow check can follow, and a condition can branch on who wrote it. The same start covers comments on ads.
The start, in the app
Click the start on the canvas and its settings open beside it.
- On which posts
- Any post or ad, ads only, posts and reels only, picked posts or your next post.
- Keywords
- Typed and pressed Enter, shown on the card as chips.
The rules of a comment start
The builder holds a flow to them, so nothing you build is refused by Meta later.
| What | The limit | Set by |
|---|---|---|
| Private replies per comment | One, the one DM Meta allows | |
| When the private reply can go | Up to 7 days after the comment | |
| What a comment flow must do | Something on the comment: a public reply, a private reply or a hide | CommentWatchDog |
| Messages before they answer | None: the chat opens when they tap or reply to the private reply | |
| Keywords on one start | 50, up to 80 characters each | CommentWatchDog |
| Instagram Live comments | Not a start | CommentWatchDog |
Meta’s rules: the Instagram and Messenger Platform private replies documentation, read 2026-10-05.
Comment flows that clean up first
Your moderation rules run before any DM goes out, on Instagram and Facebook alike.
CommentWatchDogNo Facebook posts or adsFrom each tool’s own pricing and help pages, October 2026. Logos belong to their owners.
Questions people ask
Short answers before you start.
Start a flow with Someone comments, choose which posts count and which comments (a keyword, an exact phrase or any comment), then add what should happen: a public reply under the comment, a private reply in their DMs, or both. Switch it on and every new comment that matches gets it in seconds.
Yes. Choose Your next post: the start waits, binds itself to the next post you publish, and comments on it start the flow from the moment it is up.
Has a keyword starts the flow when the comment contains any of your words, up to 50, each up to 80 characters. Capitals and accents do not matter, a keyword must start a word, common endings count (price finds prices) and longer words do not (link does not match linkedin). It works in Arabic, Chinese, Japanese and Thai. Is exactly needs the whole comment to be one of your words.
Only if you want that. How often per person can be every time, once ever, once per post, once a day or once a week; someone who already went through it is skipped quietly.
The editor flags the clash and lets you choose which one answers. Until you choose, the more specific one wins: a chosen post over every post, an exact phrase over a keyword.
Yes. A comment flow can reply under the comment, send the one private reply Meta allows, and hide the comment, in any order. Spam is handled before any of it by your moderation rules.