SOAP, also known as (Simple Object Access Protocol) is a significant protocol that was beneficial in the introduction of the widespread usage of Web services. SOAP can be called APIs. The SOAP protocol is still widely in use. Although, several organizations opted for the REST API due to its flexibility. But some people prefer the control of datatype, defined standard, and structure of SOAP.

In this article, we would be focusing on SOAP APIs, its advantages, and other subtopics that'll help you understand the protocol's place within Web service API and its history.

What is SOAP

As stated earlier, SOAP is a standard for messaging. This standard was put in place a long time ago by the World Wide Web consortium. The data format used by SOAP is XML. It uses this format to assert its response messages and request. It enforces the structure of its payloads by relying on XML Schema and some other technologies.

Both private and public APIs make use of SOAP as their interface. SOAP APIs tend to be more popular with big organizations and enterprises. This is because they consume and produce SOAP APIs.

SOAP APIs uses a pattern called Remote Procedure Call (RPC) to process method or functions. These methods and functions passed through several parameters that'll bring back a result.

SOAP is simply a protocol for messages. This protocol allows the elements of an application that has been distributed to communicate with each other. SOAP also uses lower-level protocols. One of which is HTTP (Hypertext Transfer Protocol). It determines a header structure. This structure recognizes the actions taken by several SOAP nodes concerning the message. This is also an extension of a payload structure used in conveying information.

In SOAP, messages are routed via a string of nodes. This string performs several functions. SOAP routing of messages is the process it uses to support things like security, format independence, and issuing an address. Basically, SOAP headers recognize roles. This in turn presents the SOA features that SOAP routes to. In the micro service-centric growth environment of today, stringing messages via a sequence of steps has become uncommon.

SOAP has several important aspects. One of which is its API. It is SOAP's immunity from underlying transport protocol and programming language. For instance, the sender can make use of C#, while the receivers stack depends on Java. More enterprise acquainted languages are commonly related to SOAP. Also, SOAP has implementations in Ruby, Python, and all recent programming languages.

Extensibility is also a benefit of SOAP. As the standard that it is, its specifications are purposely limited to constraints. This makes the extensibility model of the SOAP specification customizable.

Security of SOAP API

There are several examples of SOAP API. Some of which are those required to query weather or stock quotes. It is quite interesting to know that the aforementioned examples require no authentication. While valuable for a timely proof of concept, more powerful SOAP API will authorize and authenticate the API calls. This ensures that crucial business methods are only made accessible to approved parties.

For instance, HTTP Basic Auth receives a password and username when they are sent through SSL/TLS. This can be the best way to verify a user. However, it is important to know that there is no authorization or built-in role using this method. As it delivers point to point security, end to end security is often required.

WS-Security is an extension of SOAP. This extension delivers several security features for SOAP APIs. WS-Security is built on the XML Signature and XML Encryption specifications. It also interprets how to encrypt and sign SOAP messages. Additionally, it aids a number of security token layouts that include X.509, SAML, and Kerberos.

Conceivably, the most used SOAP's extension which is WS-Security allows the authorization of senders, end to end security, and extra features that organizations require in Web services.

History and Future of

SOAP first published its specification in 2000. There was a release of an initial version in 1998. It was known as XML-RPC. It included a more focused feature set like SOAP. XML-RPC permits remote procedural calls through XML. It mainly uses HTTP alone to transfer data. Interestingly, this stands to be the general protocol for SOAP. However, SOAP can technically make use of any protocol.

It took SOAP 3 years for its specification to attain the recommendation stage. Rapidly, it became the most popular approach to Web services. Before SOAP was published, there was no standard method useful for the creation of programmable interfaces used in the exchange of data among systems. SOAP brought about innovation within the enterprise. It facilitated the first surge of public APIs from organizations like Salesforce, Amazon, and eBay.

During that same time, REST APIs were formulated in a doctoral dissertation. However, the approach given to SOAP as a standard guaranteed its stay and popularity.

SOAP prevails as a crucial standard for Web services. It also drives several internal systems worldwide. For modern projects, several organizations are shifting to using REST APIs due to its microservices architecture. While techniques that are more modern leave behind a standard-based procedure of SOAP, several people crave the more nimble and flexible development process.