Xml integration and API integration are two different concept
Firstly we need to understand the meaning of travel API.
Now what is xml, the full form is extensible markup language. Generally in travel api two protocols are used xml and json. Xml is used for SOAP API and Json is used for REST API. XML is older protocol and Json is newer. So I think this much is enough for non technical people to understand that Xml API Integration and Json API Integration are two different protocol of API Integration.
Different API for B2B and B2C
There are no different API for B2C and B2B. API is used to fetch the data from the server and B2B/ B2C are part of development not data. So on same API, development of B2C, B2B, B2B2C and B2E module is possible.
Purchasing Travel API means development is included
When anyone purchases the API he/she only gets the id and password for API access and documentation. In documentation, the information of node request and responses are mentioned. The design and development with API response data is executed by travel portal development company.