LINE’s own Flex Message carousel caps out at 12 product cards per message, and quick-reply buttons at 13 — but 1CS limits product cards further, to 10 per message, because a wall of scrolling cards is harder for a shopper to act on than a short, filtered list. Here’s what each limit actually covers, and the question to ask before you send any cards at all.
How many product cards LINE lets you send
LINE’s Messaging API reference states that a Flex Message carousel holds at most 12 bubbles, and that the JSON defining the whole carousel can’t exceed 50 KB (developers.line.biz). Neither number is a soft guideline — it’s what the API accepts.
1CS sets its own ceiling lower still: a product card message sends at most 10 items, each needing at least one photo before it can appear as a card at all. It works on LINE, Facebook Messenger, and the web chat widget; Instagram and WhatsApp don’t support the scrolling card format yet.
Both of those are upper bounds, not targets. As a recommended default, start by sending 3-4 cards at a time and asking whether the customer wants to see more. Ten cards that fit neatly on a desktop preview take a lot more thumb-swiping and attention to get through on a phone screen mid-chat.
How many buttons to hand the customer
LINE’s quick-reply buttons — the row that appears above the keyboard — cap at 13 per message, per the same API reference (developers.line.biz). 1CS’s own welcome-message start buttons, shown only on LINE when a customer opens a brand-new chat, use that same ceiling of 13.
The follow-up buttons 1CS can show after every AI reply are capped much lower, at 4, and work on LINE, Messenger, and Telegram. That’s a tighter limit on purpose: this button row reappears after every single answer, so a crowded one gets harder to scan each time it resurfaces. Each button can be switched off, set to a fixed message you write once, or left for the AI to generate as a follow-up question each time.
Set up in 1CS
Turn the pieces on from two or three screens:
- Turn on “ส่งการ์ดสินค้าแบบรูปภาพ” (send product cards as photo cards) under Business > Sell products > Products, and add at least one photo per item — a product with no photo never renders as a card.
- The add-to-cart button on a card only works once AI cart is turned on; until then, 1CS tells the shopper your team will handle the order directly.
- Set the follow-up buttons from the AI Agent page, “Other” tab. Set the LINE-only welcome-message start buttons from the same AI Agent page, “ข้อความต้อนรับ” tab.
Test the cards and buttons on every channel you actually use before customers see them — a card renders differently on LINE than on Messenger or the web widget. The full walkthrough, screens and all, is in Thai: ส่ง Product Card และปุ่มตอบกลับ (Quick Reply) in the 1CS help center.
A filter question to send before the cards
Ask one short filtering question before sending any carousel, then send only the cards that match the answer:
Hi! We’ve got a few options for [product name]. Quick question first — what’s your budget range, [price range 1] or [price range 2]? Any color or size you’re set on? I’ll send over the closest matches once I hear back — no more than [3-4] at a time, easier to scroll than ten.
A card a customer actually taps beats ten they scroll past without reading. Once they’ve picked one, the next decision is whether your team or the AI takes it from there — see When a chatbot should hand the cart back to a human — and if the item is a pre-order, A pre-order deposit workflow that stops repeat status pings covers what to send next.
