Web Services is by far the most ubiquitous technology used for integration purposes. You always come across it in a B2B discussion, with either business or technical stakeholders. In Travel industry, web services account for +40% of total integrations. This technology has a broad history and many branches that make it suitable to meet a broad range of solutions. In this article, we explain the basics on web services technology, detail some of the most common extensions, such as SOAP, and provide interesting Travel industry examples on how this technology is used to solve real challenges.