# Register for event

Register a traveler for a PROGRAM_SESSION event. If userId is omitted, the logged-in user is registered. Creates a PROGRAM_TRIP child event under the session and publishes it, triggering async trip creation. Requires enableRegisterLink to be true on the session event. Returns the new PROGRAM_TRIP event ID.

Endpoint: POST /v2/events/{eventId}/register
Version: v2
Security: Bearer

## Security:

  - `Bearer` (unknown)
    http bearer

## Path parameters:

  - `eventId` (string, required)
    Event ID of the PROGRAM_SESSION event to register for.

## Request fields (application/json):

  - `userId` (string)
    User ID of the traveler to register. When omitted, the logged-in user is registered (self-registration).
    Example: a1b2c3d4-e5f6-7890-abcd-ef1234567890

## Response 200:

  - `200` (unknown)
    OK

## Response 200 fields (application/json):

  - `eventId` (string, required)
    ID of the newly created PROGRAM_TRIP event.
    Example: 56789012

  - `tripId` (string)
    ID of the trip, if already created. Present when the user was already registered.
    Example: 12345678

## Response 400:

  - `400` (unknown)
    Bad request

## Response 400 fields (application/json):

  - `debugIdentifier` (string)
    Link to debug the error internally.

  - `errorMessages` (array)

  - `errorMessages.errorCode` (string)
    Error code to identify the specific errors.

  - `errorMessages.message` (string)
    Message containing details of error.

  - `errorMessages.errorParameters` (array)
    Error message parameters.

  - `errorMessages.errorParameters.name` (string)
    Parameter name

  - `errorMessages.errorParameters.value` (string)
    Parameter value

  - `errorMessages.errorDetail` (string)
    More details about the error.

## Response 401:

  - `401` (unknown)
    Unauthorized

## Response 401 fields (application/json):

  - `debugIdentifier` (string)
    Link to debug the error internally.

  - `errorMessages` (array)

  - `errorMessages.errorCode` (string)
    Error code to identify the specific errors.

  - `errorMessages.message` (string)
    Message containing details of error.

  - `errorMessages.errorParameters` (array)
    Error message parameters.

  - `errorMessages.errorParameters.name` (string)
    Parameter name

  - `errorMessages.errorParameters.value` (string)
    Parameter value

  - `errorMessages.errorDetail` (string)
    More details about the error.

## Response 403:

  - `403` (unknown)
    Forbidden

## Response 403 fields (application/json):

  - `debugIdentifier` (string)
    Link to debug the error internally.

  - `errorMessages` (array)

  - `errorMessages.errorCode` (string)
    Error code to identify the specific errors.

  - `errorMessages.message` (string)
    Message containing details of error.

  - `errorMessages.errorParameters` (array)
    Error message parameters.

  - `errorMessages.errorParameters.name` (string)
    Parameter name

  - `errorMessages.errorParameters.value` (string)
    Parameter value

  - `errorMessages.errorDetail` (string)
    More details about the error.

## Response 404:

  - `404` (unknown)
    The specified resource was not found.

## Response 404 fields (application/json):

  - `debugIdentifier` (string)
    Link to debug the error internally.

  - `errorMessages` (array)

  - `errorMessages.errorCode` (string)
    Error code to identify the specific errors.

  - `errorMessages.message` (string)
    Message containing details of error.

  - `errorMessages.errorParameters` (array)
    Error message parameters.

  - `errorMessages.errorParameters.name` (string)
    Parameter name

  - `errorMessages.errorParameters.value` (string)
    Parameter value

  - `errorMessages.errorDetail` (string)
    More details about the error.