# Transcode a message

Transcodes the message from the Conversation API format to the
channel-specific formats for the requested channels. No message
is sent to the contact.

Endpoint: POST /v1/projects/{project_id}/messages:transcode
Version: 1.0
Security: Basic, oAuth2

## Path parameters:

  - `project_id` (string, required)
    The unique ID of the project. You can find this on the Sinch Dashboard.

## Request fields (application/json):

  - `app_id` (string, required)
    The ID of the app used to transcode the message.

  - `app_message` (object, required)
    A message originating from a Conversation API app

  - `app_message.explicit_channel_message` (object)
    Allows you to specify a channel and define a corresponding channel specific message payload that will override the standard Conversation API message types. The key in the map must point to a valid conversation channel as defined in the enum ConversationChannel. The message content must be provided in a string format. You may use the [transcoding endpoint](https://developers.sinch.com/docs/conversation/api-reference/conversation/tag/Transcoding/) to help create your message. For more information about how to construct an explicit channel message for a particular channel, see that [channel's corresponding documentation](https://developers.sinch.com/docs/conversation/channel-support/) (for example, using explicit channel messages with [the WhatsApp channel](https://developers.sinch.com/docs/conversation/channel-support/whatsapp/message-support/#explicit-channel-messages)).

  - `app_message.explicit_channel_omni_message` (object)
    Override the message's content for specified channels. The key in the map must point to a valid conversation channel as defined in the enum ConversationChannel. The content defined under the specified channel will be sent on that channel.

  - `app_message.channel_specific_message` (object)
    Channel specific messages, overriding any transcoding. The structure of this property is more well-defined than the open structure of the explicit_channel_message property, and may be easier to use.
The key in the map must point to a valid conversation channel as defined in the enum ConversationChannel.

  - `app_message.agent` (object)
    Represents an agent that is involved in a conversation.

  - `app_message.agent.display_name` (string)
    Agent's display name

  - `app_message.agent.type` (string)
    Agent's classification. It can be UNKNOWN_AGENT_TYPE, HUMAN or BOT.
    Enum: "UNKNOWN_AGENT_TYPE", "HUMAN", "BOT"

  - `app_message.agent.picture_url` (string)
    The Agent's picture url.

  - `channels` (array, required)
    The list of channels for which the message shall be transcoded to.
    Enum: "WHATSAPP", "RCS", "SMS", "MESSENGER", "VIBERBM", "MMS", "INSTAGRAM", "TELEGRAM", "KAKAOTALK", "KAKAOTALKCHAT", "LINE", "WECHAT", "APPLEBC"

  - `from` (string)
    Optional.

  - `to` (string)
    Optional.

## Response 200 fields (application/json):

  - `transcoded_message` (object)
    The transcoded message for the different channels.
The keys in the map correspond to channel names, as defined by the type
ConversationChannel.

## Response 400 fields (application/json):

  - `error` (object)

  - `error.code` (integer)

  - `error.details` (array)

  - `error.details.type_url` (string)

  - `error.details.value` (string)

  - `error.message` (string)

  - `error.status` (string)

## Response 403 fields (application/json):

  - `error` (object)

  - `error.code` (integer)

  - `error.details` (array)

  - `error.details.type_url` (string)

  - `error.details.value` (string)

  - `error.message` (string)

  - `error.status` (string)

## Response 500 fields (application/json):

  - `error` (object)

  - `error.code` (integer)

  - `error.details` (array)

  - `error.details.type_url` (string)

  - `error.details.value` (string)

  - `error.message` (string)

  - `error.status` (string)

## Response 501 fields (application/json):

  - `error` (object)

  - `error.code` (integer)

  - `error.details` (array)

  - `error.details.type_url` (string)

  - `error.details.value` (string)

  - `error.message` (string)

  - `error.status` (string)