Post share trigger

A customer forwards you a post and writes not a single word. To understand what they want you have to open the post, then type an answer. The Post share trigger handles that silent message: it asks "are you interested in this one?" and puts the customer on the right track. This guide covers building the trigger, branching on the shared post, and how this event differs from the others.

⚠️ Note: this trigger works on Instagram only. WhatsApp has no post-share event; there a shared link arrives as an ordinary text message and is caught with the keyword trigger.

In this article you will find:

• What it does
• Building the trigger
• Fields and buttons
• Branching on the shared post
• What happens when no trigger matches
• Limits and known issues
• Common mistakes and how to fix them

What it does

The trigger runs when someone sends you a post, reel or carousel by DM on Instagram. The shared content may be your own post or someone else's; the trigger catches both.

Its value lies in the fact that these messages usually arrive with no text. The customer forwards the post and says nothing; a keyword trigger has nothing to search, and if you have an Any message trigger the welcome flow runs and the customer gets "hello, how can I help" — even though they already showed you what they want.

With this trigger you write an answer for that exact moment: "If you are interested in the item you shared, shall I send you the sizes and colours?" Then you add two buttons and move the person on in a single tap.

The person's identity is known and the share arrives in their own message, so the messaging window is open; the first message goes out with its buttons, card and file intact.

Building the trigger

Let us build a product-question flow for a clothing shop.

1. Open an empty flow with New automation from the Automations list.
2. On the Flow tab, click the When… box on the canvas.
3. Press Add trigger in the panel on the side.
4. Pick Post share from the list.
5. If your account has more than one channel connected, pick the Instagram account from the Channel list.
6. Connect the start box's Next output to a Message step.
7. Write "I can see the item you shared 👀 I can send you the sizes and the price." and add the buttons Size chart and Price.
8. Tick Wait for a written reply on the message step, so the flow also picks up a customer who types instead of tapping.
9. Connect each button's output to its own step.
10. Press Publish at the top right. Your automation is now running.

Fields and buttons

The trigger card holds two items.

Channel — Which account the trigger runs on. It appears only when more than one channel is connected.

Remove — The cross at the top right of the card deletes the trigger.

The note under the card sums the behaviour up: "Runs when someone shares a post or reel with you." There are no keyword, match mode or post selection fields here. You make the post distinction not in the trigger but in a condition step inside the flow, described next.

Branching on the shared post

The shared post's ID is written into the session and read in the flow with the Post condition. This is the trigger's greatest strength: one flow can answer differently for different products.

1. Add a Condition step after the start.
2. Choose the Post rule type.
3. Set the operator to equals and put the relevant post's ID in the value. You can take the ID from the places that use the post picker, or from the post list on the Stats screen.
4. Connect the True output to that product's own answer and the False output to a general one.

You can use the same condition to ask "is this our post?": put your own campaign post's ID in and give a different answer to people sharing someone else's content.

💡 The Post condition is only filled by the comment and share triggers. In a flow started by a keyword, a story or a schedule it is always empty, and it stays empty on a WhatsApp account too.

What happens when no trigger matches

Because a post share arrives in the person's own message, if no trigger matches this event the message is evaluated again as an ordinary message. Keyword, Any message and Default reply are tried in that order.

So without a post share trigger the customer lands in your welcome flow. If they also wrote something alongside the share, that text is compared with your keywords; a customer writing "do you have this" may land in your stock flow.

Post share is an explicit trigger: it cuts the person's running session and starts this flow. Flows whose interruption setting is turned off on the Settings tab are shielded from that.

Limits and known issues

• The trigger works on Instagram only.
• You cannot choose a post in the trigger; make the distinction with the Post condition.
• There is no keyword filter. To branch on the text written alongside the share, use the Last reply condition in the flow.
• The shared post does not count as an image for the Incoming attachment condition; the condition says "no attachment". If the customer also attached a photo of their own, the condition sees that photo.
• If the shared post has been deleted or the account is private, the ID still arrives but the post's content cannot be reached.
• A shared story does not reach this trigger; stories have the story reply and story mention triggers.
• The trigger only runs while the automation is Live.

Common mistakes and how to fix them

• Assuming you know what the customer shared. The flow cannot see the post's image, only its ID. Sentences like "I see you liked this lovely piece" read strangely on the wrong post. Use neutral wording.
• Building a separate automation per product. Build one share flow and make the product distinction with Post conditions inside it. Ten separate automations are unmanageable and start competing for priority.
• Expecting text. Most shares carry no text, so a flow that leans on the Last reply condition usually lands on the "False" branch. Write a full answer for the general branch too.
• Leaving the re-entry rule open. A customer forwarding five items they liked gets the same message five times. Once a day on the Settings tab is usually enough.
• Confusing it with a story share. If someone mentioned you in their story this trigger does not run; that is a separate event.

If shares are arriving but the flow does not start, see the automation never starts guide or get in touch with our Support team.

Related articles

• Post comment trigger
• Story reply trigger
• Flow context conditions
• How triggers work
• The automation never starts