# Introduction

**Seamlessly incorporate Booking.com inventory into your metasearch engine.**

## Metasearch Connect API

Metasearch Connect API is dedicated for integration of metasearch engines. Initially, it is made compatible with
the [Demand API](/demand/docs/open-api/demand-api/) to simplify the transition for metasearch providers that currently
use it.
Later, Metasearch Connect API will offer a new set of endpoints that are tailored for metasearch-specific use cases.

The transition will be performed in two phases:

1. During phase 1, the changes you will need to make will be minimal: switching to a new API address and implementing a
new token-based authentication mode. However, this will require extensive monitoring on our end; therefore, the
process will be coordinated via account managers.
2. Phase 2 may require some more effort on your part, but it will not be purely a technical change. New
endpoints will also offer more features specific to metasearch engines and extend to our inventory in other vertical
sectors of the travel market (e.g., flights).


## Endpoints

The Connect API endpoints are currently grouped into two main collections, also referred to as API layers.
Each collection provides a different area of functionality.

### Demand API V3 Compatibility Layer

The endpoints in this layer are grouped under the base path `/demand-api-v3-compatible` and use the interface compatible
with Demand API V3. These endpoints are meant for easy transition in the short term and provide functionality specific
to the accommodations sector of the travel market.

### Demand API V2 Compatibility Layer

The endpoints in this layer are grouped under the base path `/demand-api-v2-compatible` and use the interface compatible
with Demand API V2. These endpoints are meant for easy transition in the short term and provide functionality specific
to the accommodations sector of the travel market.

Attention
All current endpoints exist for compatibility with the Demand API and will be used only for transition. We suggest not
migrating from `demand-api-v2-compatible` to `demand-api-v3-compatible`, or vice versa. In H2 2024, we will start adding
new collections of endpoints with a different interface, and we will ask all metasearch providers to migrate to the
latest version.

## Features

The Connect API is designed to provide flexible, scalable, and expansible access to the Booking.com inventory. For
compatibility, all the features in Demand API that are being used by metasearch providers are also present in the
Connect API.

### Designed for future expansion

Currently, the Connect API offers access to Booking.com's inventory using the Demand API interfaces:


```mermaid
graph LR
    P1(Metasearch provider 1) --> V3E1(/demand-api-v3-compatible/endpoint-1)
    P1(Metasearch provider 1) --> V3EN(/demand-api-v3-compatible/endpoint-N)
    P2(Metasearch provider 2) --> V2E1(/demand-api-v2-compatible/endpoint-1)
    P2(Metasearch provider 2) --> V2EN(/demand-api-v2-compatible/endpoint-N)
```

Future versions of the Connect API will provide access to the Booking.com's inventory in various sectors of the travel
market by adding new, vertical-specific API collections, such as attractions or flights. There will be a transition
period allowing the metasearch providers to migrate from the old endpoints.


```mermaid
graph LR
    P(Metasearch provider) --> AE1(accommodations/endpoint-1)
    P(Metasearch provider) --> AEN(accommodations/endpoint-N)
    P(Metasearch provider) --> TE1(attractions/endpoint-1)
    P(Metasearch provider) --> TEN(attractions/endpoint-N)
    P(Metasearch provider) --> FE1(flights/endpoint-1)
    P(Metasearch provider) --> FEN(flights/endpoint-N)
```