Send RCS message

post

https://api.transmitmessage.com/v2/rcs/messages

This endpoint is in beta and may change in future versions.
Sends an RCS message to a single recipient.

The message can be text (content_type: text), a single image or video (content_type: media),
or a standalone card or carousel (content_type: rich_card). Any message can carry suggestions:
reply chips, links and dial buttons shown under it.

For media, including card media, we check each file when you send the request. The request fails
with 400 if a file isn't publicly reachable over https, redirects, doesn't respond in time, or
has an unsupported, mismatched or oversized file type.

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Body Params

sender

string

required

The RCS agent ID assigned to your registered agent.

Unlike SMS, WhatsApp, and MMS, RCS messages do not come from a phone number.
They are always sent through an agent.

Must be a registered RCS agent identifier.
Example: DemoSender
Can be alphanumeric or numeric.

recipient

string

required

The destination number for delivery.
Can be either in local format or in international format.
For international format, it should follow the E.164 standard.

Examples of conversions to E.164 format:

Australia: 0438 333 061 → 61438333061
UK: 07123 456 789 → 447123456789

content_type

string

enum

required

Type of the message content. Must match the key used in content.

text — a text message, sent in content.text
media — a single image or video, sent in content.media
rich_card — a standalone card or a carousel, sent in content.rich_card

Allowed:

content

required

The message content to be sent.

text: supports both Basic RCS messages (160 characters) and Simple RCS messages (3072 characters), with UTF-8 and emoji support.
media: one image or video by public URL, without a caption.
rich_card: one card, or a carousel of 2–10 cards, each with a title, description, image or video, and up to 4 buttons.

Every content type can carry up to 11 suggestions shown under the message.

sms_fallback

object

Provides intelligent fallback for non-RCS capable devices and carrier delivery issues. If the RCS message fails, the SMS will send the configured message to the recipient instead.

Without it, a failed RCS message is not sent by SMS.

message_ref

string

A reference supplied by your system. Maximum length of 500 characters.

This reference is included in webhook events so you can relate events with the original message.

For example, being able to relate a Link Hit event to a specific sent message.

Responses

200OK

400Input Validation Error

401Unauthorized

500Internal Server Error