Quick answer. A carousel is a horizontally swipeable set of rich cards in one RCS message — great for showing multiple products, menu items, or properties. A carousel must contain at least 2 and at most 10 cards, all cards share the same width, and all media must be the same height; 2–5 cards tends to engage best. Each card can carry its own media, title, description, and up to four suggestions.
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" } } ] }
] } } } }