Create an outbound agent chat message

post/v2.1/chat/outbound/messages
Requires any one of these rolesAbout roles
org.permission.message.create

The API key or user must hold at least one of them.

Send an agent outbound chat message on an existing session using an API token.

customerId and from (org user id of the sender) are required. Provide session with either body or attachments. trackingId follows the same session matching rules as inbound message routes.

Optional auto: true marks the message as AI/automation-authored so it is excluded from human-interaction FRT. Omitting auto is valid and leaves the field unset (backward compatible).

About this resource

Chat conversations

The server-side chat API lets your backend take part in Kustomer chat with a regular API key. It can open chat sessions for a customer, post messages as the customer, an agent or an assistant, show typing, import bot conversations and record satisfaction ratings.

A chat session is a Kustomer conversation on the chat channel, seen from the chat side. Its ID is the conversation ID, so the same conversation appears in the agent desktop and in the customer's chat widget or app, and you can read it with the conversations API too. Sessions are usually created by the chat SDKs when a customer starts a chat. These v2.1 endpoints do the same jobs from your server, for custom chat front ends, messaging bridges and bots that answer before a human does. Anything you post is delivered in realtime to the customer's open chat on every device.

A session stays active until the chat is ended or deleted. Listing with active=true returns only active sessions that have at least one message.

Identity: customerId and trackingId

These endpoints never use a chat key or a customer's chat login token. Every request names the customer in customerId, and Kustomer checks it against the session: a mismatch fails with 403. trackingId is the chat SDK's ID for a visitor's browser or device. It's optional, but when a session has one, any trackingId you send must match. Creating a session without one reuses the tracking ID from the customer's latest chat session, if there is one; handoff imports never set one.

Use a server-side API key with the roles each endpoint lists, never a chat key, which must hold only org.tracking.

Who a message is from

Endpoint Appears as
POST /v2.1/chat/messages The customer (direction: in). Returns 202 Accepted; the message is processed asynchronously.
POST /v2.1/chat/assistant/messages The customer, replying inside an assistant (bot) flow, so the assistant continues from where it is.
POST /v2.1/chat/outbound/messages An agent: from is the Kustomer user ID. Add auto: true for bot or AI replies so they don't count as a human first response.
POST /v2.1/chat/outbound/assistant/messages An assistant line, attributed to from. Send exactly one of body, meta.template or attachments.

Message bodies are up to 10,240 characters. Typing indicators are ephemeral and never stored. Your service owns their lifecycle: sending a message doesn't hide one, so send typing: false when you're done, and resend typing: true about every three seconds for long answers.

Which endpoint to use

To Call
Open a chat for a customer, optionally starting an assistant POST /v2.1/chat/sessions
Import a conversation your own bot already had POST /v2.1/chat/handoff
List a customer's or visitor's chats GET /v2.1/chat/sessions
Read a chat's messages GET /v2.1/chat/sessions/{id}/messages
Post as the customer POST /v2.1/chat/messages or, in an assistant flow, POST /v2.1/chat/assistant/messages
Post as an agent or bot POST /v2.1/chat/outbound/messages
Post as an assistant POST /v2.1/chat/outbound/assistant/messages
Show or hide typing POST /v2.1/chat/outbound/typing
Record a CSAT rating or comment PUT /v2.1/chat/satisfaction-responses/{id}

A handoff takes 2 to 100 messages, including at least one inbound and one outbound, and sorts them by date; active: false creates the conversation already closed. When you pass assistant on session create, Kustomer posts the assistant's greeting, and if that fails the session is still created. Session lists are paginated, newest first by lastMessageAt, and don't include messages. The CSAT response must already exist, created by Kustomer for the chat's survey; this call fills it in, and sending answers marks it commented rather than rated.

RelatedServer-side chat APIHow chat worksCustomer identityConversations

Request body

application/jsonrequired
Any of
any
customerIdstringrequired

24-character hexadecimal ObjectId (case-insensitive).

fromstringrequired

Required. Org user id who sends the outbound message.

trackingIdstring

24-character hexadecimal ObjectId (case-insensitive).

sessionstring

24-character hexadecimal ObjectId (case-insensitive).

bodystring
min length 1 · max length 10240
attachmentsarray<ObjectId>
min items 1
idstring

Optional client-supplied message id.

brandstring

24-character hexadecimal ObjectId (case-insensitive).

campaignstring

24-character hexadecimal ObjectId (case-insensitive).

maybeInitialOutboundboolean
createNewConversationboolean
array<object>
messageTemplateobject

Rich template. Must be exactly one template variant (text, quick_replies, deflection, mll, list, or answer_button_feedback).

object
autoboolean

Optional. When true, marks the message as AI/automation-authored (excluded from human-interaction FRT and related denorms). Omit the field entirely for backward-compatible behavior.

externalIdstring
max length 256
importedAtstring<date-time>
createdAtstring<date-time>
sentAtstring<date-time>

Responses

Created

object