TriggerCustomer.ioReal-timeUpdated June 2026

When does Customer.io fire on email opens?

Short answer: Drop the "Customer.io → Email Opened" trigger on your workflow canvas, add filters if you want them, and publish. It fires within seconds of the event in Customer.io, not on a polling schedule.

Use this trigger All 4 Customer.io triggers

Anatomy

What this trigger looks like in a workflow.

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

In the builder

Trigger

Email Opened

When the matching event happens

when email openedwhen an email is openedwatch for email openedon email openednew email opened

What this trigger returns

for the curious

You don’t need to read this. Tiny Command 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.

{
  "event": "email.opened",
  "customer_id": "cust_123"
}

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
event	string	"email.opened"
customer_id	string	"cust_123"

Pairs with

Drop these actions after Email Opened.

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 Email Opened.

How does the Email Opened trigger work in Customer.io?

Fires the first time a recipient opens an email. Useful for engagement-based scoring or for "warm lead — open detected, fire follow-up sequence" cross-app patterns.

Is the Email Opened trigger real-time?

Yes. Email Opened uses webhooks or push subscriptions, not polling. Your workflow fires within seconds of the event happening in Customer.io.

What data does Email Opened return?

The full event payload from Customer.io. 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 Email Opened 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 Customer.io admin permissions to use Email Opened?

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