TriggerCustomer.ioReal-timeUpdated May 2026
When does Customer.io fire on new subscribers?
Short answer: Drop the "Customer.io → Customer Subscribed" 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.
Anatomy
What this trigger looks like in a workflow.
Drop it on the canvas. Configure a couple of fields. Publish.
In the builder
Trigger
Customer Subscribed
When the matching event happens
when customer subscribednew customer subscribedwatch for customer subscribedwhen a customer subscribeson customer subscribed
What this trigger returns
for the curiousYou 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": "customer.subscribed","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 | "customer.subscribed" |
| customer_id | string | "cust_123" |
Pairs with
Drop these actions after Customer Subscribed.
FAQ
Questions about Customer Subscribed.
How does the Customer Subscribed trigger work in Customer.io?
Fires when a customer subscribes to a Customer.io segment or list. The base hook for "they joined → start the welcome journey" or "qualified → add to BDR's outreach queue" cross-app workflows.
Is the Customer Subscribed trigger real-time?
Yes. Customer Subscribed uses webhooks or push subscriptions, not polling. Your workflow fires within seconds of the event happening in Customer.io.
What data does Customer Subscribed 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 Customer Subscribed 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 Customer Subscribed?
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.
More triggers
Other Customer.io triggers.
Trigger
Email Delivered
Fires when the recipient mail server accepts the message. Useful for verifying "did the transactional email actually deliver?" workflows.
TriggerEmail Link Clicked
Fires when a recipient clicks a tracked link in a Customer.io email. Payload includes the link URL and recipient. High-signal behavioural hook — branch on URL to route engagement to the right downstream automation.
TriggerEmail Opened
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.
Build a workflow on this trigger.
One trigger. 4+ downstream actions. Zero glue.
