A Web Service is a software program that uses XML to exchange information with other software via common internet protocols. In a simple sense, Web Services are a way of interacting with objects over the Internet.
A web service is,
- Language Independent.
- Protocol Independent.
- Platform Independent.
- It assumes a stateless service architecture.
- Scalable (e.g. multiplying two numbers together to an entire customer-relationship management system).
- Programmable (encapsulates a task).
- Based on XML (open, text-based standard).
- Self-describing (metadata for access and use).
- Discoverable (search and locate in registries)- ability of applications and developers to search for and locate desired Web services through registries. This is based on UDDI.
Key Web Service Technologies, - XML- Describes only data. So, any application that understands XML-regardless of the application’s programming language or platform-has the ability to format XML in a variety of ways (well-formed or valid).
- SOAP- Provides a communication mechanism between services and applications.
- WSDL- Offers a uniform method of describing web services to other programs.
- UDDI- Enables the creation of searchable Web services registries.