Different organizations and books have different views on what defines web services. Some of these are as follows.
A web service is simply an XML-based information exchange system that employs the use of the Internet for direct communication. The systems used may be in the form of programs, messages, objects, or documents.
A web service is a modular, self-contained, dynamic, and distributed software which can be described, located, published, or initiated over the network to create processes, products as well as supply chains. This software can be local, web-based or distributed. A web service is usually built with the help of unfastened standards like HTTP, HTML, TCP/IP, XML, and Java.
What Is A Web Service?
A web service is any service which:
- Is accessible on the Internet
- Employs the use of XML encoding for transferring information
- Are independent of programming languages
- Makes use of a common language
- Can be discovered through a simple mechanism
The topic of web services require a lot more details that are covered in dedicated tutorials on this playlist we have compiled on Youtube. 
How Web Services Work
Web services make communication possible through many applications by employing the use of open standards like XML, SOAP, HTML, and WSDL. They make use of:
- SOAP to send and receive messages. Learn more about SOAP Web Services on This YouTube tutorials Series about SOAP web services.
- WSDL to notify if the service is available.
- XML to mark the data
This makes it possible for you to build Java-enabled web services on a Mac, which will be easily reached from the visual- basic program that runs on your windows.
What Are the Benefits of Web Services?
Making Use of Existing Functions on Networks
Web services are managed codes that can be accessed and activated by making use of HTTP requests. A web service allows you to use the functionality of your code that already exists over the network. Once the function is exposed on the network, then there is a possibility of other programs making use of its functionality.
Interoperability
A web service makes it possible for different applications to communicate with each other and share services and data. Various software suites can also use web services. For instance, .NET or Java can communicate with a VB web services and the other way around. Web services ensure the independence of technology and application platforms.
Reduced Communication Cost
A web service makes use of SOAP rather than the HTTP protocol; therefore, you can employ the Internet to implement web services. This makes it much less costly when compared to other solutions such as EDI/B2B. Apart from the preference of SOAP over HTTP, it is possible to implement web services through other reliable transport mechanism such as FTP.
Characteristics of Web Services
Today, Web Services are independent applications that can be distributed, found, and fabricated on the Internet. Web Services offer a standard method for interoperability between various programming applications.
eXtensible Markup Language (XML) gives the extensibility and dialect nonpartisanship that is the key for the interoperability of Web Services. They perform functions that can incorporate anything from basic inquiry results to complex business forms. Once a Web Service is sent, different applications can find and invoke it. At present, Web Services require human communication for recognizable proof and execution.
Based on XML
A web service employs the use of XML during data transportation as well as data representation. The use of XML removes the need for any operating system, networking or platform binding. This makes web services extremely interoperable applications at their core level.
Loosely Tied
A consumer using a web service is not tied directly to the web service. The interface of the web service can change with time without affecting the ability of the client to make use of the service. If the system were to be tightly coupled, it means that the server logic and the client are both tied together, and a change in one requires a corresponding update on the other for smooth functioning. Using a loose system makes it easier to manage and gives room for simpler integration among various systems.
Coarse-Grained
Using object-oriented technologies such as C# release their services by making use of individual methods. Producing a C# program means that you have to create many fine-grained methods that are then integrated into a coarse-grained service used by a client or another service.
The interfaces and the businesses that are released should be coarse-grained. Web services technology gives a natural way for coarse-grained services to apply the right amount of business logic.
Supports Document Exchange
Two major advantages of XML is representing data generically and also representing complex documents. These documents can be as simple as a current address and can also have the complexity of an entire book. The transparent exchange of documents is possible on web services that facilitate business integration.