# Pre-Book

## Overview <a href="#sd-pre-bookapi-overview" id="sd-pre-bookapi-overview"></a>

This document provides a comprehensive overview of the transactions and functionality available in the **RateGain Pull Connectivity Model**. The core component of this model is **UltraDirect**, and the APIs discussed in this documentation pertain specifically to **XML UltraDirect**.

The document includes:

\
a. **Detailed Message Formats**

* A complete description of all fields (XML elements and attributes) used in request and response messages.
* This serves as a valuable resource for developers, supplementing the XML message definitions provided in the HotelML XML Schema Definition (XSD) files.

b. **Message Examples**

* Sample request and response messages illustrating key functionalities.

c. **Process and Transaction Flows**

* Typical workflows to guide implementation and integration.

Below is a summary of the **UltraDirect Prebook Transactions** for quick reference:

| Pre-Book | Re-check process and availability for a specific room type and rate plan immediately before making a booking |
| -------- | ------------------------------------------------------------------------------------------------------------ |