01 / ConceptHow the format works
The carousel is a single ad slot that contains multiple slides. A thin progress bar sits across the top of the unit. Each slide is displayed for 5 seconds, then the next slide takes over. When the last slide finishes, the loop returns to the first.
The novel part is in the timing of the ad call. Just before a slide is about to appear, the format fires an ad request for that specific slot. The creative is loaded and rendered moments before it becomes visible. This way the slide that the user actually sees is one that was just requested — so viewability is high — and the carousel can keep cycling fresh inventory throughout the page session.
02 / PlacementsWhere it lives on the page
This showcase demonstrates two placements running simultaneously: a 300×600 display unit and a sticky bottom bar anchored to the bottom of the viewport. Both run their own independent carousel rotation.
- 300×600 — Desktop sidebar On desktop the half-page unit lives in the right rail, sticky to the top of the column as the reader scrolls.
- 300×600 — Mobile in-content On mobile the same creative is rendered inline, between paragraphs of the article. Switch to mobile view to see it.
- Sticky bottom — Desktop (90px / 180px) A slim 90px bar in display mode. When a video slide is being served, the bar expands to 180px and shows the video in a constrained-width player so the transition between slides feels gentler.
- Sticky bottom — Mobile (100px / 180px) A slim 100px bar in display mode. Like the desktop variant, it expands to 180px for video slides with the player anchored to the left.
03 / Video slidesThe exception to the 5-second rule
When a video creative is served into the carousel, it doesn't follow the timer. Instead the slide remains active for as long as the video runs, and rotation only resumes once playback completes. The progress bar reflects the actual playback position rather than a fixed countdown.
The sticky bottom bar in this showcase contains a video slide — watch the bottom of your screen and you'll see the bar expand and the player take over for the duration of the clip before handing back to the standard 5-second slides.
In production the carousel would call your ad server with the slot ID and slide index. On onSlideEnd it triggers the next request. Each slide can be a different ad from a different buyer — the carousel is an inventory multiplier, not just a single creative with multiple panels.
04 / Try it yourselfSwitch between views
Use the toggle in the top right to flip between the desktop layout and a mobile device emulation. The mobile view also activates automatically when this page is loaded on a mobile-sized screen. You'll see how the 300×600 unit moves from sidebar to in-content, and how the sticky bottom bar adapts its height between display and video modes.
Keep watching the units — every five seconds (or whenever the video ends) the next slide is requested and rendered. That's the carousel ad format in motion.
— End of showcase. Built for demonstration purposes. All ads shown are fictional placeholders.