What Is a SOAP API?
A messaging specification for information exchange between systems and applications is called Simple Object Access Protocol (SOAP). A SOAP API is designed in a manner that is more structured and codified than other application programming interfaces (APIs). Compare SOAP to the United States Postal Service. Sending and receiving communications across systems (and within enterprise applications) is made dependable and trustworthy with its help. Although it can be slower than rival architectural forms like REST, it is more traditional, well-established, and trustworthy.
An overview of SOAP APIs
The SOAP standard was developed in the latter part of the 1990s to enable companies to transfer data between internal networks. Introduced during the web's maturation, SOAP's architectural principles are less closely connected with HTTP than REST; it can also use other protocols, even though it uses HTTP primarily as a conduit for the messages being passed around. REST is more of a style, whereas SOAP provides much more information about the content and encoding of messages as well as the structure of requests and responses. Stated differently, while developing APIs, SOAP emphasizes the message, while REST emphasizes specifying them as resource.
SOAP uses XML as the data format for messages being sent and received by an API client, and it provides four distinct dimensions to the API protocol:
Envelope: Defining the structure of the message.
Encoding: Rules for expressing the type of data.
Requests: How each SOAP API request is structured.
Responses: How each SOAP API response is structured.
When to use SOAP APIs
As a component of a common communication protocol, SOAP makes use of XML to facilitate the sharing of structured data in distributed settings. Applications written in various programming languages and operating systems can communicate with one another thanks to SOAP.
SOAP API Vs REST
Simple Object Access Protocol, or SOAP for short, is a secure API development method that uses XML encoding to encode data. The more versatile REST (Representational State transport) APIs allow the transport of data in a variety of formats, such as XML, HTML, plain text, JSON, and more. Both REST and SOAP have advantages and downsides when compared.
Advantages of utilizing SOAP APIs
Although SOAP is known for its versatility, it also has highly tight implementation rules. Similar to other methods of delivering APIs, SOAP transports data over HTTP; however, it can also employ user data protocol (UDP), transmission control protocol (TCP), and simple mail transport protocol (SMTP) to exchange messages. This makes it possible to move data, material, and media with more flexibility.
In addition, SOAP APIs offer the following benefits over REST APIs:
- REST necessitates the use of HTTP, whereas SOAP is independent of language, transport, and even platform.
- Because SOAP is so safe, it's ideal for sensitive data handling systems, such online banking apps and financial services.
- Instead of relying solely on direct point-to-point communication, SOAP functions effectively in distributed enterprise systems.
- Because SOAP includes built-in error handling capabilities, deciphering the cause of a failed request is simple.
Cons of SOAP API
REST might be a preferable choice in some circumstances, even though SOAP can be very helpful in others. Among the disadvantages are:
- Caching API calls is not supported by SOAP.
- The complexity of SOAP is significantly higher than that of REST, which may affect performance.
- REST is significantly more flexible than SOAP.
- REST is typically faster than SOAP.
Use cases for SOAP APIs
Among the most typical use cases for SOAP APIs are the following:
Bank transfers: Bank transfers necessitate communication between branches or banks, which could entail making several calls to various web sites. In addition, security is crucial for this use case.
Booking flights: To verify availability and obtain information on flight prices, several web providers must be contacted, just like with bank transactions.
Billing services: Individuals in industries such as telecommunications must establish connections with multiple systems in order to provide billing data, which frequently contains sensitive information.
Navigation firms: In order to determine the optimal routes, shipping and transport companies must compile data from numerous sources.
City management: To guarantee that the city is operated effectively, SOAP APIs link numerous city administration procedures. Every one of these procedures, from controlling traffic lights to running the sewage system, must function consistently.
Conclusion
Although it can be more expensive, the SOAP protocol offers a stronger foundation for APIs than the more flexible REST method. It can take longer to onboard new developers who are unfamiliar with SOAP's older techniques and to evolve and revise APIs when using SOAP. However, for the enterprise's critical backbone apps and integrations, the expense is justified. Recall the analogy with the national postal service? The envelope, encoding, request, and answer structure of SOAP, along with its adaptability to protocols like HTTP, TCP, UDP, and SMTP, make it a dependable method for defining and managing APIs at scale inside the organization.