RCS (Rich Communication Services) enables rich, branded messaging in the native device messaging app — including rich cards, carousels, suggested actions, media messages, location messages, read receipts, and typing indicators. When a device does not support RCS, configure automatic fallback to SMS.

Prerequisites

A provisioned RCS Sender Agent (request via Sinch — requires carrier approval).
A Conversation API app in the same region as your RCS Agent.
At least one webhook configured for delivery reports and inbound messages.

SDK Reference

RCS Agents

An RCS Agent is your business identity on RCS — includes brand name, logo, description, and verification status. Agents must be approved by carriers before use. Provisioning is handled through Sinch.

Message Types

Message Type	When to Use	Key Indicators in User Prompt
Text	Simple text messages	"send a message", no special formatting
Media	Images, videos, PDFs	"send an image", "share a photo", file/media URLs
Choice	Interactive buttons/suggestions	"with options", "with buttons", "choose between"
Card	Rich card with image + buttons	"rich card", "card with image", "product card"
Carousel	Multiple swipeable cards	"carousel", "swipeable cards", "multiple products"
Location	Share coordinates/map	"send location", "share coordinates", "map"
Template	Pre-defined reusable messages	"use template", "send template"

Detection logic: Check for structural keywords (carousel, card, buttons) → media indicators → location indicators → default to text.

Rich Cards

Title max 200 chars, description max 2000 chars. See Card Message.

Carousels

2-10 swipeable cards. 1 card renders standalone. Up to 3 outer choices below. See Carousel Message.

Choice Messages

Interactive suggestions as chips: suggested replies and suggested actions (open URL, dial, show location, share location, create calendar event). See Choice Message.

Media Messages

Images, videos, audio, PDFs. Up to 100 MB. Formats: JPEG, PNG, MP4, GIF, PDF. Auto-detected from URL. See Media Message.

Location Messages

Transcoded to text with a location choice button on RCS. See Location Message.

Channel-Specific Properties

Property	Description
`RCS_WEBVIEW_MODE`	Size of webview for OpenUrl actions
`RCS_CARD_ORIENTATION`	Orientation of rich card
`RCS_CARD_THUMBNAIL_IMAGE_ALIGNMENT`	Image preview alignment in rich card

Capability Check

Check if a device supports RCS before sending: POST /v1/projects/{project_id}/capability:query with channel: "RCS". Result delivered via webhook CAPABILITY trigger. See Capability trigger.

Channel Fallback (RCS to SMS)

Set channel_priority_order: ["RCS", "SMS"] and include both channel identities. Add SMS_SENDER in channel_properties. Fallback triggers SWITCHING_CHANNEL delivery report. See Messages API Reference.

Typing Indicators

Send composing_event via POST /events:send with channel: "RCS". See Events API.

Code Examples (by message type)

Text: Text Message
Card: Card Message
Carousel: Carousel Message
Choice: Choice Message
Media: Media Message
Location: Location Message
Template: Template Messages
List: List Message

For SDK examples, see the SDK Reference links above.

RCS Gotchas

Carrier and device support varies. RCS is not universally available. Always configure SMS fallback.
Agent provisioning takes time. Carrier review can take days or weeks.
Media dimensions matter. Rich card media must fit predefined heights. Use 4:3 (960x720) for best results.
Carousel truncation. Cards share uniform height. Long content is truncated.
No template system. Unlike WhatsApp, RCS does not require pre-approved templates.
Read receipts are native. RCS provides read receipts automatically.
Rich messages degrade on non-RCS. Carousels sent via SMS fallback become plain text. Test fallback rendering.
Media caching. URLs cached up to 28 days. Rename files to force refresh.