Article · Email and SMS

Which five Klaviyo flows should a subscription box brand build first?

By Super Simple Co · Updated 2026-10-30

A subscription box brand that connects Klaviyo to Supr can build five flows from the events Supr sends: a renewal reminder (Subscription Renewing Soon), a skipped box follow-up (Subscription Next Order Date Changed), a failed payment flow (Subscription Payment Failed), a cancel save follow-up (Subscription Cancelled) and a win-back series (Subscription Win-Back 1, 2 and 3). Each one is a Klaviyo flow triggered by the metric of that name.

Who this is for: For subscription box marketers who use Klaviyo and want email flows for reminders, skips, failed payments, saves and win-backs.

How it works, in plain words

In Klaviyo, open Settings > Account > API keys and create a Private API key. Full Access works. If you choose Custom, set Events to Full and Accounts to Read. A Read-Only key cannot send events.
In Shopify, open Supr Bundle & Subscription App > Settings > Integrations > Klaviyo, paste the key into Private API key and click Connect.
Under Test an event, pick a notification and a subscription (or our sample) and click Send test event. The test goes to your store's contact email and is marked as a test, so you can keep it out of a live flow. The metric appears in Klaviyo once its first event has arrived.
In Klaviyo, create a flow and choose the Metric as the trigger.

Under Who sends your customer emails, you decide who sends each email. Build and switch on the Klaviyo flow before you hand an email over, because a customer receives nothing until the flow for that metric is live. To keep our emails and also get every event in Klaviyo, turn on Also send Klaviyo the events we do not hand over.

In your Klaviyo template, use event fields such as event.customerPortalUrl for the link to manage the subscription, event.linesSummary for a readable list of what is in the box, and event.nextBillingDate for the date. To show each product with its image and price, loop over event.lines.

Flow 1: renewal reminder

Trigger: Subscription Renewing Soon. It is sent before a subscription repeats, at the lead time you choose under Settings > Notifications on the Upcoming subscription renewal card (from 1 day to 1 month before). Show the date, the contents with linesSummary and a button to customerPortalUrl so the subscriber can skip or change the box before it ships.

A reminder is a reminder only: the charge happens automatically either way. Keep the copy short, and put the date at the top.

Flow 2: skipped box

Trigger: Subscription Next Order Date Changed. Supr has no metric named for a skip. A skip in the portal moves the next order date, so it sends this metric, and so does any other change to the date. Add a flow filter on the skippedNextOrder property being true, and send a thank-you that confirms the new date and offers a reason to stay (the next box's theme, for instance).

Test it before you rely on it: skip a box on a test subscription and open the event in Klaviyo to check the properties you filter on. If you also sell boxes that reveal their contents, Subscription Box Revealed is a separate metric for the day a box is revealed.

A subscriber who moves the date by hand also triggers this metric, which is why the filter matters.

Flow 3: failed payment

By default a failed renewal is retried 3 times, 1 day apart, and then marked Failed. You change that under Settings > Dunning. Spread your messages to match that schedule, and read the help article Dunning Settings before you set the delays.

Metric	Means	What the flow says
Subscription Payment Failed	A renewal failed because of the customer's payment, so they need to fix their card	Ask them to update the card, with a button to customerPortalUrl
Subscription Renewal Failed	A renewal failed for a reason the customer cannot fix	No action needed, a short note that you are on it
Subscription Failed	The subscription failed after its retries ran out	Last call: how to restart it

Flow 4: cancel save

Trigger: Subscription Cancelled. The offer that tries to keep a subscriber at the moment they click cancel is the app's own cancellation flow, set up under Grow (see How to build a cancellation flow for a subscription box). Klaviyo cannot interrupt that screen. What a Klaviyo flow can do is follow up after it, with the properties the event carries: cancellationReason, cancellationComment, renewalsAtCancellation and, when an offer was shown, retentionIncentiveType, retentionIncentiveValue and retentionIncentiveAccepted.

Branch on cancellationReason: a short note about a pause for "too much", a different box for "not for me". For subscribers who paused instead, Subscription Paused carries pauseReason, and Subscription Pause Reminder, Subscription Pause Win-Back and Subscription Resuming Soon cover the rest of a pause.

Flow 5: win-back

Triggers: Subscription Win-Back 1, Subscription Win-Back 2 and Subscription Win-Back 3, sent 14, 30 and 60 days after a subscription is cancelled. They exist when you switch on the matching emails in the cancellation flow, under After cancellation: Win-back emails. The 30 and 60 day emails can carry a one-time discount, and the event then carries winBackUrl, winBackCode and winBackSavings for your template.

By default win-back emails go only to customers who cancelled from the customer portal, not to subscriptions you cancelled yourself or that failed payments cancelled. Each customer receives each email once.

If you want customers to restart without checkout, turn on Reactivate cancelled subscriptions under Settings > Customer portal and link to the portal in the email.

What Klaviyo is not for here

The moment of cancelling: that is the cancellation flow in the app.
Staff notifications and the Email me a copy switches: they keep coming from the app.
Erasing a customer's data: remove them in Klaviyo as well as in Shopify, because erasing in Shopify does not remove them from Klaviyo.

Questions

Do I have to hand every email to Klaviyo?

No. Choose Supr, Klaviyo, or Choose per notification. Each customer email has one sender.

Will the flows fire for test events?

Test events are marked as tests so you can filter them out of a live flow. Add that filter before you switch a flow on.

Is there a flow for a single failed payment attempt?

Subscription Payment Failed and Subscription Renewal Failed are sent when a renewal fails. How many times depends on your retry settings under Settings > Dunning.

What if Klaviyo rejects an event?

We send that customer our own email instead, so nobody is left with nothing, and the Klaviyo page shows Klaviyo rejected the last event with a Re-check key button.

Every setting is covered in the help center: Using Klaviyo.

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