What Is SOAP API and Does It Still Work? – MakeUseOf

SOAP, or Simple Object Access Protocol, is a protocol specification for exchanging structured data in web services. Does it still work? Find out here!
SOAP, meaning Simple Object Access Protocol, is another type of API used by top companies. But it's not so popular anymore, as its use seems to be dwindling in modern apps. Want to learn more about this classic API architecture, despite being a REST fan?
Sit tight as we explain what SOAP is and see if it's still in use today.
SOAP relies on web service description language (WSDL), an extensible markup language (XML) for sending data between software.
And considering the rigid structure of XML, data transmitted by SOAP API is verbose and looks more complex than the more vogue representational state transfer (REST) architecture.
When sending to or receiving data from a SOAP API, you're transmitting closely packed items wrapped in individual identifying tags. The arrangement of data in SOAP follows a rigid access pattern and structure in a dedicated file. This makes SOAP highly protocol-driven.
In addition to transferring data over the hypertext transfer protocol (HTTP), SOAP also supports more primitive protocols, including file transfer protocol (FTP), transmission control protocol (TCP), and simple mail transfer protocol (SMTP). So, it offers transfer flexibility across various networks and platforms.
That said, while other transfer protocols make primitive data exchange possible, it's more practicable to serve SOAP over an HTTPS network.
SOAP uses web service (WS) security, a dedicated message encrypting extension. So, this fills the gap while sending data using data transfer protocols other than HTTPS.
It also combines this with the secure socket layer (SSL), a security token that serves websites over HTTPS. So, security-wise, SOAP has an advantage over REST, which relies solely on HTTPS for security.
Related:What Is an XML File and How Can You Open and Use It?
Additionally, the format of the data returned by a SOAP API is readily programmed. This makes it easily integrable across several programming technologies.
Thus, SOAP API is extensible, agnostic, and neutral to protocol.
SOAP, like any API framework, has a generic structure. That said, the architecture of a SOAP API is similar to that of an HTML DOM.
A SOAP API has the following structure:
Originally designed for and first used by Microsoft in 1998, SOAP is considered old and complex. And it has drastically been replaced by the more flexible REST architecture, which serves more than 70 percent of public APIs today.
Nonetheless, some top companies still use SOAP—especially as a transfer agent between in-house services.
SOAP API supports both stateless and stateful communications. This biphasic capability is another reason why it remains the framework of choice in some cases.
When you use it in a stateful data exchange, it allows efficient information tracking across multiple requests. Although this complex operation may clog up the server, it still makes SOAP a preferred option when building complex applications that need an extra layer of security and chaining.
A stateless transfer, on the other hand, doesn't overload the server's memory. So, this feature is equally handy if the aim is to reduce runtime and get a better server performance.
But rather than use SOAP to handle stateless communications, web services now prefer to use the REST framework, which is more flexible and completely stateless.
The Microsoft Dynamics program, for example, uses SOAP API to provide business-to-business solutions to big companies.
Since SOAP is ACID-compliant, stateful, offers WS security encryption, and comes with SSL, it is a popular API architecture for banking and financial applications transactions.
The stateful nature of SOAP API maintains database integrity during transactions. Even when an error occurs in a request, it tracks it and reverses compromised data.
Related:What Does API Stand For? Examples of How to Use APIs
Invariably, this explains the meaning of its compliance with the ACID (Atomicity, Consistency, Integrity, and Durability) concept:
SOAP reigns in the API domain as one of the most secure messaging channels between software. Despite being complex, slow, old, and heavy, it's still indispensable in many companies today. While modern APIs are easy to use, SOAP API might be your best bet in some situations, after all.
And besides creating one yourself, you might find yourself in a scenario where it's the only applicable option that can deliver a solution in your software. So learning more about SOAP is a valuable addition to your API knowledge.
If you’re looking for an explanation of what Rest API is, and how you can use it, you’re in the right place.
Idowu is passionate about anything smart tech and productivity. In his free time, he plays around with coding and switches to the chessboard when he’s bored, but he also loves breaking away from routine once in a while. His passion for showing people the way around modern tech motivates him to write more.
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