Image vs iframe
Should a countdown be an image or an iframe?
In short
The answer is decided by the surface, not by preference: email gets an image because it has no other option, and the web gets an iframe because it is strictly better there. What matters is understanding the trade-off each one carries.
In email, an image is the only thing that works
Email clients do not execute JavaScript and strip iframes, so a countdown in the inbox has to be a picture that a server regenerates on each open. Everything else about email countdowns follows from this constraint: the fixed pixel size, the animation limits, the baked-in background that dark mode cannot recolor.
On the web, an iframe is better in every dimension
A web embed renders live HTML: the digits update every second rather than looping a short animation, the type stays sharp at any zoom or pixel density because nothing is a bitmap, and it costs your page no JavaScript because the timer runs in its own document. It also isolates styling in both directions — your CSS cannot leak into it and it cannot leak into your page.
<iframe src="https://cdn.tikio.io/embeds/a1b2.html" title="Offer ends soon" width="480" height="140" frameborder="0" scrolling="no" style="border:0;"></iframe>The one thing an iframe costs you: clicks
A click inside an iframe does not bubble up to a surrounding link, so wrapping the embed in an anchor silently does nothing. Put your call to action on a button next to the timer instead. In email the opposite is true — the image is just an image, so wrapping it in a link works exactly as you expect and a ticking countdown is one of the most clicked elements in a campaign.
Keeping both in sync
The two formats should come from one design and one deadline, otherwise your landing page and your campaign eventually disagree — usually right after someone edits one of them. In tikio both come from the same link: the deadline is stored once, the URLs differ only by extension, and editing the deadline updates the page and already-sent emails together.
.gif for the inbox · .html for the page · one link, one stored deadlineLast updated: 2026-09-30.
FAQ
Questions, answered
Can I use the iframe version in a newsletter platform like Ghost or beehiiv?
On the published web version of the post, yes. In the emailed version, no — those platforms strip iframes because no email client renders them. Use the image form for the email and the iframe for the web post.
Is a GIF or a PNG better for email?
A GIF, because it animates. A PNG would be sharper and support partial transparency, but it would show a single frozen frame — correct at the moment of opening and motionless afterwards.
Does the iframe hurt Core Web Vitals?
Not if you give it explicit width and height, which the generated snippet does — that prevents layout shift. It also adds no JavaScript to your bundle and does not block rendering of your page.
- Client compatibility
- Apple Mail frozen timer
- Gmail dark mode
- Evergreen merge tags
- Sizes and limits
- Outlook first frame
- Wrong time
- Blurry timer
- Stops after a minute
- Klaviyo flows
Setting one up? See guides for your email platform or website embed guides.
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