How to Set Up a Birthday Flow in Klaviyo (Shopify Guide)

TL;DR: Klaviyo can send birthday emails, but collecting birthdays? That’s on you. Here’s how to set it up – and a shortcut if you don’t want the hassle.

Klaviyo is great for email marketing. Abandoned carts, welcome series, post-purchase flows – it handles all of that beautifully. So when merchants want to add birthday emails, Klaviyo seems like the obvious choice. But there’s a catch that trips up almost everyone. (Just want birthday emails working today? Skip to the Happy Birthday App for Shopify.)

The Part Nobody Mentions

Here’s what Klaviyo’s own docs say: “You must collect birthdays as a profile property on your customers’ profiles.”

Translation: Klaviyo doesn’t collect birthdays. You need to figure that out yourself. Klaviyo just sends the email once you somehow have the data.

Three ways to get birthday data into Klaviyo:

1. Add a date field to your popup – Except now your popup asks for email AND birthday, which tanks conversion
2. Import a CSV – Great if you already have birthdays somewhere (you probably don’t)
3. Connect an app that collects them – This is what most merchants end up doing

Why Popups Don’t Work for Birthdays

Think about this from your customer’s view. They just landed on your site. A popup appears asking for their email – fine, that’s normal. But also their birthday? Weird. Feels invasive. Many people just close the whole thing.

Now compare that to asking on the thank you page after checkout. They just bought something. They already trust you with their credit card. A quick “want a birthday surprise next year?” feels natural, not creepy. Way higher conversion.

Actually Building the Klaviyo Flow

Let’s say you’ve somehow got birthday data in Klaviyo. Here’s what to do:

1. Go to Flows, click “Create Flow”
2. Pick “Date Property” as your trigger
3. Select whichever field stores birthdays (needs at least one profile with data or it won’t show up – fun surprise there)
4. Set timing: day of birthday or a few days before, morning delivery, recipient’s timezone
5. Turn on yearly repeat (otherwise it sends once and never again)
6. Design your email, add a discount code
7. Go live

Not rocket science, but definitely more steps than you’d expect for something this common.

The Date Format Headache

Klaviyo needs dates in specific formats – YYYY-MM-DD or MM/DD/YYYY. Import a spreadsheet with “March 15” or “15/03/1990” and your flow just… won’t trigger. No error message, just silence.

This bites people constantly. They set everything up, wait for a birthday to roll around, nothing happens. Then they discover their dates are wrong and have to re-import everything.

Discount Code Complications

You’ll want unique codes per customer so people can’t share them on coupon sites. Klaviyo can do dynamic codes, but you need to set it up in Shopify first, then wire it to Klaviyo. Another layer of fiddling.

The Easier Path

Look, Klaviyo is fantastic if you’re already deep into it. But for birthday emails specifically, you’re bolting complexity onto a platform that doesn’t really want to do this job.

The Happy Birthday App was built for exactly this:

• Collects birthdays via checkout widget – no popup friction
• Sends emails automatically – no flow building
• Unique codes included – no Shopify setup required
• 12 languages built in – try doing that with 12 Klaviyo flows

Or use it as a data source: the app collects birthdays, syncs to customer profiles, and you still build your flow in Klaviyo if you prefer that editor. Best of both worlds.

When to Stick with Klaviyo

Makes sense if:

• You already have birthday data sitting in profiles
• Birthday emails are part of a bigger Klaviyo strategy you’re running
• You genuinely enjoy building flows

When to Use a Dedicated App

Better choice if:

• You don’t have birthday data yet (this is most stores)
• You want this done in 30 minutes, not an afternoon
• You sell internationally and need multi-language emails
• You’d rather set it up once and forget about it

Bottom Line

Klaviyo birthday flows work fine. But most merchants asking “how do I send birthday emails in Klaviyo” are really asking “how do I collect birthdays” – and that’s the part Klaviyo doesn’t help with. Same goes for Omnisend and Mailchimp, if you’re comparing platforms.

If you want the power of birthday emails without the setup headaches, check out the Happy Birthday App for Shopify. Or just try it free and see.