The Checkfront PHP SDK by Checkfront interacts with the API to access booking data that can be utilized to build rentals and reservations applications. Resources include instructions to set up the SDK with token and OAuth2 authentication.
Travel reservation site Expedia starting working on its Expedia API back in 2009, according to the changelog. It has three APIs, covering hotels, flights and cars. Don't be shy. Expedia has been expecting you. The Expedia developer site has all the warmth and care of a fine bed and breakfast. They clearly want to invite you in, make you comfortable, and get your development project of the ground. Though they do have a couple hoops to jump through, as well.
Holidays and restful breaks are an important part of maintaining a happy and healthy lifestyle, and there are a lot of services out there that help to make holiday planning easy by eliminating the need to search through reams of accommodation options. The problem is, as much as the information offered online is extensive, it doesn't always guarantee that the chosen hotel will live up to how it's been portrayed in the pictures or that it will provide the desired experience. Escapio is a German booking portal that takes online hotel booking a step further. The service categorises it's hotels according to lifestyle criteria and accommodation types; all hand-picked, unique and of a specific quality standard. Escapio also makes this data available via the Escapio API.