Every email you send can now grow your referral program. Connect ReferralCandy with Customer.io and the newsletter your customers already open carries their personal referral link, new subscribers become advocates within seconds of joining your list, and the moment someone’s referral converts, a journey can pick it up with a thank-you. The program stops being a page customers have to find and becomes part of every conversation you’re already having with them.
That changes what a referral campaign can look like. Instead of a standalone ask that competes for inbox attention, referral becomes a layer across your whole messaging calendar — product launches, digests, post-purchase flows, win-backs — each one quietly carrying a link that’s personal to the reader. And because referral activity flows back into Customer.io as events, the milestones that used to happen silently inside ReferralCandy can now drive the same journeys the rest of your marketing runs on.
Here’s what the integration does, in both directions: your Customer.io audience flows into your referral program, and your referral activity flows back into Customer.io.
Put referral links in the emails you already send
Once connected, ReferralCandy can write each advocate’s unique referral link back to their Customer.io profile as a custom attribute — rc_referral_link_<campaign short code> — along with a referralcandy_advocate flag. Those attributes show up in Customer.io’s email editor as merge tags, ready to drop into any campaign or newsletter.
That turns your regular sending into a referral channel. A product update, a monthly digest, a post-purchase flow — any of them can carry a link that’s personal to the reader, without a separate referral email competing for attention in the inbox.
Bring your Customer.io audience into your program
Your most likely advocates are already on your list — the repeat buyers, the reviewers, the people who open everything. You can import your Customer.io contacts into ReferralCandy as advocates, either everyone at once or a specific segment if you’d rather launch with the customers most likely to share. Imports run on demand, and re-running a sync updates existing contacts rather than duplicating them. Contacts need an email address to import, which in practice they already have.
Build journeys around referral moments
The integration can send real-time events to Customer.io profiles as things happen in your program:
- RC - Enrolled — a person joined a campaign
- RC - Subscribed to campaign emails — their subscription status changed
- RC - Purchase referred by profile detected — someone they referred made a purchase, with the amount and currency
- RC - Reward earned — they earned a reward, with the type, value, and coupon code where applicable
These events can trigger Customer.io automations and journeys the same way any other event does. A thank-you flow when someone’s first referral converts. A reminder a few days after a reward lands. A follow-up for advocates who enrolled but whose link hasn’t produced a referral yet. The moments that matter in a referral program stop happening silently and become moments your email platform can see, celebrate, and build on.
Enroll new subscribers as they arrive
There’s also a real-time path in the other direction. Set up a reporting webhook in Customer.io pointing at ReferralCandy, enabled for Subscribed events, and new subscribers are enrolled in your referral campaign within seconds of joining your list. Someone signs up for your newsletter and walks away with a referral link before your welcome email has finished sending.
How it works
- Connect. Open the integration from your ReferralCandy dashboard or Shopify admin, enter your Customer.io App API key, and select your workspace region (US or EU).
- Import. Choose all people or a specific segment to bring in as advocates.
- Enable write-back. Add your Site ID and Track API key to write referral links back as attributes.
- Turn on events and the webhook. Stream referral events into Customer.io, and optionally add the subscriber webhook for real-time enrollment.
One thing to know about email
ReferralCandy never sends email through Customer.io. Both platforms send independently, which means newly imported advocates will receive whatever ReferralCandy emails you have enabled — welcome, reminders, rewards. If you want Customer.io to own all of that messaging, disable ReferralCandy’s campaign emails before you sync. You’ll find the toggles under Campaigns, then your campaign, then Emails.
Get started
The full setup walkthrough — API keys, write-back, events, and the webhook — is in the setup guide. If you’re already running Customer.io, connecting the two takes one API key to start.