# Send a message for a booking

Sends a plain-text message on the booking's operator↔partner conversation. Bookable stores the
message and relays it over email to the other participant, who can reply from their normal mail client.

The delivery target is derived from the caller's role — there is no recipient field:
- Integration Partner — delivered to the venue operator (direction: partner_to_operator).
- Venue group operator — delivered to the integration partner (direction: operator_to_partner).

Attachments cannot be sent via this endpoint; add them by replying to the relay email instead.

Endpoint: POST /bookings/{bookingId}/messages
Version: 2.0.0
Security: Live

## Path parameters:

  - `bookingId` (string, required)
    The composite booking ID (e.g. 29|CO|6a3e866a4989b3b73d78f011|B)
    Example: "29|CO|6a3e866a4989b3b73d78f011|B"

## Header parameters:

  - `X-Correlation-ID` (string)
    An optional ID which you can use to track transactions across multiple systems. It can have any value, but we recommend avoiding . characters.
Mirrored back in a response header.
    Example: "11C46F5F-CDEF-4865-94B2-0EE0EDCC26DA"

  - `X-Partner-Reference` (string)
    Required for Bookable Agents. Specifies the partner reference for whom the booking is being made.
This header must contain a valid partner reference when making requests with the agent:write scope.

## Request fields (application/json):

  - `body` (string, required)
    Plain-text message body. Delivered to the other conversation participant.
    Example: "Could you please accommodate a high chair for us?"

  - `direction` (string)
    Sandbox-only test override. Forces the absolute message direction so a partner can trigger their own message.received webhook (send operator_to_partner) against their registered sandbox callback — without a real operator or an inbound email round-trip. Ignored outside the Sandbox environment, where the direction is derived from the caller's role. When set in Sandbox the email relay is skipped (webhook-only): the message is stored and the webhook fires, but no email is sent.
    Enum: "operator_to_partner", "partner_to_operator"

## Response 201 fields (application/json):

  - `id` (string, required)
    Unique message identifier
    Example: "msg_abc123"

  - `subject` (string,null)
    Email subject line
    Example: "Table for Jane Smith"

  - `body` (string, required)
    Message body text
    Example: "Could you please accommodate a high chair for us?"

  - `senderEmail` (string,null)
    Email address of the sender
    Example: "partner@example.com"

  - `senderName` (string,null)
    Display name of the sender
    Example: "Jane Smith"

  - `direction` (string, required)
    Absolute message direction: operator_to_partner = the venue operator sent it; partner_to_operator = the integration partner sent it.
    Enum: "operator_to_partner", "partner_to_operator"

  - `attachments` (array,null)
    Attachment metadata (bytes are exchanged over email, not via this API).

  - `attachments.filename` (string, required)
    Attachment file name
    Example: "floorplan.pdf"

  - `attachments.contentType` (string,null)
    MIME content type
    Example: "application/pdf"

  - `sentAt` (string, required)
    ISO 8601 timestamp when the message was sent

## Response 400 fields (application/json):

  - `type` (string)
    A URI reference [rfc9457] that identifies the problem type. This specification encourages that, when dereferenced, it provides human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank".

  - `title` (string, required)
    A short, human-readable summary of the problem type. It SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

  - `status` (integer, required)
    The HTTP status code [rfc9457, Section 3.1.12] generated by the origin server for this occurrence of the problem.

  - `detail` (string)
    A human-readable explanation specific to this occurrence of the problem.

  - `code` (string, required)
    Error code in the format RESOURCE-X-NNN where X is R (retryable) or N (non-retryable). See ErrorCatalog.md for all error codes.
    Example: "VALID-N-001"

  - `isRetryable` (boolean, required)
    Indicates whether the error is retryable. If true, the request may succeed if retried. If false, the request will fail again with the same input.

  - `traceId` (string)
    Request trace identifier for debugging and correlation purposes.
    Example: "0HNJ2BG2TU3BU:00000001"

  - `errors` (object,null)
    Validation errors dictionary mapping field names to arrays of error messages. Only present for validation errors (VALID-N-001).
    Example: {"Date":["Availability date cannot be in the past."],"EndTime":["EndTime must be after StartTime."]}

## Response 401 fields (application/json):

  - `type` (string)
    A URI reference [rfc9457] that identifies the problem type. This specification encourages that, when dereferenced, it provides human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank".

  - `title` (string, required)
    A short, human-readable summary of the problem type. It SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

  - `status` (integer, required)
    The HTTP status code [rfc9457, Section 3.1.12] generated by the origin server for this occurrence of the problem.

  - `detail` (string)
    A human-readable explanation specific to this occurrence of the problem.

  - `code` (string, required)
    Error code in the format RESOURCE-X-NNN where X is R (retryable) or N (non-retryable). See ErrorCatalog.md for all error codes.
    Example: "VALID-N-001"

  - `isRetryable` (boolean, required)
    Indicates whether the error is retryable. If true, the request may succeed if retried. If false, the request will fail again with the same input.

  - `traceId` (string)
    Request trace identifier for debugging and correlation purposes.
    Example: "0HNJ2BG2TU3BU:00000001"

  - `errors` (object,null)
    Validation errors dictionary mapping field names to arrays of error messages. Only present for validation errors (VALID-N-001).
    Example: {"Date":["Availability date cannot be in the past."],"EndTime":["EndTime must be after StartTime."]}

## Response 403 fields (application/json):

  - `type` (string)
    A URI reference [rfc9457] that identifies the problem type. This specification encourages that, when dereferenced, it provides human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank".

  - `title` (string, required)
    A short, human-readable summary of the problem type. It SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

  - `status` (integer, required)
    The HTTP status code [rfc9457, Section 3.1.12] generated by the origin server for this occurrence of the problem.

  - `detail` (string)
    A human-readable explanation specific to this occurrence of the problem.

  - `code` (string, required)
    Error code in the format RESOURCE-X-NNN where X is R (retryable) or N (non-retryable). See ErrorCatalog.md for all error codes.
    Example: "VALID-N-001"

  - `isRetryable` (boolean, required)
    Indicates whether the error is retryable. If true, the request may succeed if retried. If false, the request will fail again with the same input.

  - `traceId` (string)
    Request trace identifier for debugging and correlation purposes.
    Example: "0HNJ2BG2TU3BU:00000001"

  - `errors` (object,null)
    Validation errors dictionary mapping field names to arrays of error messages. Only present for validation errors (VALID-N-001).
    Example: {"Date":["Availability date cannot be in the past."],"EndTime":["EndTime must be after StartTime."]}

## Response 404 fields (application/json):

  - `type` (string)
    A URI reference [rfc9457] that identifies the problem type. This specification encourages that, when dereferenced, it provides human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank".

  - `title` (string, required)
    A short, human-readable summary of the problem type. It SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

  - `status` (integer, required)
    The HTTP status code [rfc9457, Section 3.1.12] generated by the origin server for this occurrence of the problem.

  - `detail` (string)
    A human-readable explanation specific to this occurrence of the problem.

  - `code` (string, required)
    Error code in the format RESOURCE-X-NNN where X is R (retryable) or N (non-retryable). See ErrorCatalog.md for all error codes.
    Example: "VALID-N-001"

  - `isRetryable` (boolean, required)
    Indicates whether the error is retryable. If true, the request may succeed if retried. If false, the request will fail again with the same input.

  - `traceId` (string)
    Request trace identifier for debugging and correlation purposes.
    Example: "0HNJ2BG2TU3BU:00000001"

  - `errors` (object,null)
    Validation errors dictionary mapping field names to arrays of error messages. Only present for validation errors (VALID-N-001).
    Example: {"Date":["Availability date cannot be in the past."],"EndTime":["EndTime must be after StartTime."]}

## Response 422 fields (application/json):

  - `type` (string)
    A URI reference [rfc9457] that identifies the problem type. This specification encourages that, when dereferenced, it provides human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank".

  - `title` (string, required)
    A short, human-readable summary of the problem type. It SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

  - `status` (integer, required)
    The HTTP status code [rfc9457, Section 3.1.12] generated by the origin server for this occurrence of the problem.

  - `detail` (string)
    A human-readable explanation specific to this occurrence of the problem.

  - `code` (string, required)
    Error code in the format RESOURCE-X-NNN where X is R (retryable) or N (non-retryable). See ErrorCatalog.md for all error codes.
    Example: "VALID-N-001"

  - `isRetryable` (boolean, required)
    Indicates whether the error is retryable. If true, the request may succeed if retried. If false, the request will fail again with the same input.

  - `traceId` (string)
    Request trace identifier for debugging and correlation purposes.
    Example: "0HNJ2BG2TU3BU:00000001"

  - `errors` (object,null)
    Validation errors dictionary mapping field names to arrays of error messages. Only present for validation errors (VALID-N-001).
    Example: {"Date":["Availability date cannot be in the past."],"EndTime":["EndTime must be after StartTime."]}

## Response 500 fields (application/json):

  - `type` (string)
    A URI reference [rfc9457] that identifies the problem type. This specification encourages that, when dereferenced, it provides human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank".

  - `title` (string, required)
    A short, human-readable summary of the problem type. It SHOULD NOT change from occurrence to occurrence of the problem, except for purposes of localization.

  - `status` (integer, required)
    The HTTP status code [rfc9457, Section 3.1.12] generated by the origin server for this occurrence of the problem.

  - `detail` (string)
    A human-readable explanation specific to this occurrence of the problem.

  - `code` (string, required)
    Error code in the format RESOURCE-X-NNN where X is R (retryable) or N (non-retryable). See ErrorCatalog.md for all error codes.
    Example: "BOOK-N-001"

  - `isRetryable` (boolean, required)
    Indicates whether the error is retryable. If true, the request may succeed if retried. If false, the request will fail again with the same input.

  - `traceId` (string)
    Request trace identifier for debugging and correlation purposes.
    Example: "0HNJ2BG2TU3BU:00000001"