A two-card carousel (simplified):
{ "contentMessage": { "richCard": { "carouselCard": {
"cardWidth": "MEDIUM",
"cardContents": [
{ "title": "Margherita", "description": "$12",
"media": { "height": "MEDIUM", "contentInfo": {
"fileUrl": "https://shop.example/marg.jpg" } },
"suggestions": [ { "reply": { "text": "Add",
"postbackData": "add_marg" } } ] },
{ "title": "Pepperoni", "description": "$14",
"media": { "height": "MEDIUM", "contentInfo": {
"fileUrl": "https://shop.example/pep.jpg" } },
"suggestions": [ { "reply": { "text": "Add",
"postbackData": "add_pep" } } ] }
] } } } }
In SimplyRCS, carousels like this are assembled and reused from the content library rather than hand-written per send.
The rules a carousel has to satisfy are short, and breaking any of them causes a render failure rather than a warning:
- Between 2 and 10 cards. One card is a rich card, not a carousel.
- One card width for the whole carousel, either small or medium.
- Identical media height across every card.
- Up to four suggestions per card.
- Every media URL publicly reachable for the life of the message.
Beyond the spec, engagement drops off well before the ten-card ceiling. Two to five cards is the range that performs, because the carousel is a decision aid and a long swipe becomes a browsing task the person defers. Put the strongest option first: the first card is the only one guaranteed to be seen, and cards past the third are viewed by a small fraction of recipients.
The format fits situations where the person is genuinely choosing between comparable things. A restaurant sending tonight’s specials, a retailer showing three sizes back in stock, an agent sending four properties that match a saved search, a clinic offering three appointment slots. In each case the cards are alternatives and the suggestion on each one commits to that choice, which is what makes the tap meaningful. Using a carousel to show one product from several angles wastes the format, because there is no decision for the buttons to capture.
Plan the fallback deliberately. A carousel has no SMS equivalent, so a recipient without RCS receives flattened text or an MMS of the first image, and the comparison the carousel existed to present is gone. Write that fallback as a short message with a link to the same set of options on your site rather than accepting an automatic flatten. Because carousels also fail the capability check more often than plain text does, expect a higher fallback share on a carousel send than on a text send to the same list.
A carousel is one of the three RCS message formats; each card follows the rich card rules, and the bot builder has a carousel node that saves the card a customer taps as a variable.