TriggerTrelloReal-timeUpdated June 2026

How do I trigger when a Trello attachment is added?

Short answer: In TinyCommand, add the Trello Attachment Added trigger to a workflow and publish. It listens through a Trello webhook and fires your workflow within seconds of the event, with no polling and no code. Add a filter if you only want some events to start a run.

Trigger workflows on Attachment Added in Trello — start free All 7 Trello triggers

Trigger workflows on Attachment Added in Trello — start free

Anatomy

What this trigger looks like in a workflow.

Drop it on the canvas. Configure a couple of fields. Publish.

In the builder

Trigger

Attachment Added

When the matching event happens

when an attachment is added to a cardon attachment addednew attachment addedwatch for attachment addedwhen attachment added

What this trigger returns

for the curious

You don’t need to read this. TinyCommand auto-maps every field into the visual picker so downstream nodes can pull values by clicking. We show it here for power users who want to know what’s on the wire.

{
  "card": "Sample Card",
  "board": "Project Board",
  "event": "addAttachmentToCard"
}

Output shape

Fields available to downstream nodes.

Every field below can be referenced by name in any action or filter that comes after this trigger.

Field	Type	Example
card	string	"Sample Card"
board	string	"Project Board"
event	string	"addAttachmentToCard"

Pairs with

Drop these actions after Attachment Added.

Add Labels to Message

Gmail · Email

Add Reaction

Slack · Communication

Add Sheet Tab

Google Sheets · Spreadsheets & Databases

Create Company

HubSpot · CRM & Sales

FAQ

Questions about Attachment Added.

How does the Attachment Added trigger work in Trello?

Fires when an attachment is added to a Trello card. Use to copy the file to S3/Drive for backup, virus-scan, or to extract text for downstream processing.

Is the Attachment Added trigger real-time?

Yes. Attachment Added uses webhooks or push subscriptions, not polling. Your workflow fires within seconds of the event happening in Trello.

What data does Attachment Added return?

The full event payload from Trello. The output shape table on this page lists every field, its type, and an example value so you can map fields into downstream nodes.

Can I filter Attachment Added so only some events start a workflow?

Yes. Add a Filter node right after the trigger and match on any field, whether that's subject, sender, status, or anything else in the payload. Workflows only continue when the filter passes.

Do I need Trello admin permissions to use Attachment Added?

For most Trello accounts a standard user can authorize the trigger. Some Trello plans require an admin to enable third-party webhooks. Check Trello's docs if the trigger fails to register.