How to add an evergreen countdown timer to a Klaviyo flow

How it works

A DynaMail countdown reads its deadline from the widget, unless the image URL carries a referenceDate= parameter, which wins. So the trick is to let Klaviyo write a different date into each recipient’s image URL. Klaviyo fills in template tags when it sends the email, which means the date is fixed for that recipient from then on: reopening the email later shows less time left, not a fresh countdown.

This is a long-standing request. In a 2021 Klaviyo Community thread (opens in a new tab), a flow builder asked for “the specific Klaviyo timestamp so that the timer starts from the time the email is sent”. Method 1 below does that with tags from Klaviyo’s own date reference.

Method 1: a deadline a few days after the email is sent

1. 1

   Create and save a countdown widget

   Make a countdown in DynaMail with the design you want and any date; the saved widget supplies the look and the timezone. The free countdown generator works, and a free account lets you edit the design later.

2. 2

   Open the flow email

   For a new email, Klaviyo’s flow article says to drag the email component from the sidebar onto the flow canvas, click the card, then click Select template to create the content. For an existing flow email, click its card on the canvas.

3. 3

   Add an HTML block and paste this

   Add an HTML block where the timer should go (Klaviyo’s documented block for timers), clear it, paste the code below and apply the change.

   Deadline 3 days after send

   Copy

   {% today "%Y-%m-%d" as today %}
   <img src="https://img.dynamail.io/widgets/YOUR-WIDGET-ID/render.gif?referenceDate={{ today|days_later:3 }}T23:59:59&amp;r={{ email|urlencode }}" alt="Time left on your offer" width="600" height="196" style="display:block;border:0;" />

   What each part does:

   • {% today "%Y-%m-%d" as today %} is Klaviyo’s documented date tag. Klaviyo says it must come before any use of {{ today }}.
   • {{ today|days_later:3 }} prints the date three days after the message is sent, as YYYY-MM-DD. Change 3 to the number of days you want.
   • T23:59:59 is plain text that completes the date, so the offer runs to the end of that day in the widget’s timezone. As long as Klaviyo’s date and the widget share a timezone (see the note below), everyone gets at least three full days.
   • r= is optional open tracking: the recipient’s email, URL-encoded with Klaviyo’s urlencode filter.
4. 4

   Preview with a recent event, then send a live test

   Klaviyo’s preview can use a real profile and, for flow emails, a recent event. Check that the timer shows the time left to the date you expect, then send a live test to yourself before switching the email to Live.

Method 2: a deadline you already store

If the deadline already lives on the profile (a trial end, a coupon expiry) or on the event that triggers the flow, put that value in the URL instead. Klaviyo’s personalization reference uses dot notation, {{ person.property_name }}, for names without spaces; an event property is {{ event.property_name }}.

{% if person.offer_expires_at %}
<img src="https://img.dynamail.io/widgets/YOUR-WIDGET-ID/render.gif?referenceDate={{ person.offer_expires_at|urlencode }}&amp;r={{ email|urlencode }}" alt="Time left on your offer" width="600" height="196" style="display:block;border:0;" />
{% endif %}

• The {% if %} wrapper, from Klaviyo’s conditional logic reference, skips the timer for profiles without the property. Without it, an empty referenceDate counts as missing, and those profiles see a countdown to the date saved on the widget instead.
• Keep the property name free of spaces. Klaviyo’s lookup form for other names needs quote marks, which do not belong inside an HTML attribute.
• urlencode protects characters such as spaces and the + in a timezone offset.
• DynaMail reads ISO 8601 dates and times, such as 2026-11-27T09:00:00 or 2026-11-27T09:00:00-05:00. A value without an offset is read in the widget’s timezone.

What this cannot do

• It cannot start the clock when the email is first opened. The deadline is set when Klaviyo sends the email, or by the date you store.
• Klaviyo’s documented date filter works in whole days. For a window in hours, store the exact deadline and use Method 2.
• The usual image caveats apply: Apple Mail may load the image early, and classic Outlook may show only the first frame. The basic Klaviyo countdown guide covers both.