Customer.io Hello World

Overview

Create a minimal working Customer.io integration: identify a user (create/update their profile), track an event, and send a transactional email. This covers the three fundamental Customer.io operations.

Prerequisites

• customerio-node installed (npm install customerio-node)
• CUSTOMERIO_SITE_ID and CUSTOMERIO_TRACK_API_KEY configured
• CUSTOMERIO_APP_API_KEY configured (for transactional email example)

Instructions

Step 1: Identify a User (Create/Update Profile)

// hello-customerio.ts
import { TrackClient, RegionUS } from "customerio-node";

const cio = new TrackClient(
  process.env.CUSTOMERIO_SITE_ID!,
  process.env.CUSTOMERIO_TRACK_API_KEY!,
  { region: RegionUS }
);

// identify() creates the user if they don't exist, or updates if they do.
// The first argument is your internal user ID (immutable — use DB primary key).
await cio.identify("user-123", {
  email: "[email protected]",          // Required for email campaigns
  first_name: "Jane",
  last_name: "Doe",
  plan: "pro",
  created_at: Math.floor(Date.now() / 1000),  // Unix seconds, NOT milliseconds
});

console.log("User identified in Customer.io");

Key rules:

• id (first arg) should be your immutable database ID — never use email as ID
• email attribute is required if you want to send email campaigns
• created_at must be Unix timestamp in seconds (not ms) — Math.floor(Date.now() / 1000)
• All custom attributes are stored on the user profile and usable in segments + Liquid templates

Step 2: Track an Event

// Track a custom event on the user's activity timeline.
// Events trigger campaigns — the event name must match exactly in the dashboard.
await cio.track("user-123", {
  name: "signed_up",                   // snake_case, matches campaign trigger
  data: {
    signup_method: "google_oauth",
    referral_source: "product_hunt",
    timestamp: Math.floor(Date.now() / 1000),
  },
});

console.log("Event tracked in Customer.io");