---
title: "POST /v1/bookings/{id}/extras"
method: POST
path: "/bookings/{id}/extras"
tags: ["BookingExtras"]
---

# POST /v1/bookings/{id}/extras

`POST /bookings/{id}/extras`

Add a SINGLE extra (delta-add). Body: { extra_id: "ex_X", quantity }.
Quantity defaults to 1. If the same extras_id is already on the
booking, the existing line's quantity accumulates rather than a
duplicate row being inserted (matches native portal behaviour).

Refuses (422) if the extra is already in the booking's package as
an included feature — customer would otherwise be double-charged.

## Path parameters

- `id` string, required

## Request body

- object
  - `extra_id` string, required
  - `quantity` integer

## Response `200`

- string

## Other responses

- `422` — Validation error

---

[API](https://skmtc.dev/boothzen/apis/boothzen-api-v1.md) · [All operations](https://skmtc.dev/boothzen/apis/boothzen-api-v1/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/boothzen/boothzen-api-v1/revisions/a5ae040e3ba3/schema)