REST versus SOAP. It’s been an issue for a while now. And really, they’re just two answers to the same question: how to access web services. But deciding one over the other can be surprisingly difficult. SOAP (Simple Object Access Protocol) is a standards-based web services access protocol that has been around for a long time. Originally developed by Microsoft, SOAP isn’t as simple as the acronym would suggest. REST (Representational State Transfer) is another standard, made in response to SOAP’s shortcomings. It seeks to fix the problems with SOAP and provide a simpler method of accessing web services. What about GraphQL? Of course, GraphQL has recently made a huge splash, which we’ve spoken of at length in other articles. But it’s still not as standardized as REST and SOAP, so in this article we’re just going to focus on those two. Both SOAP and REST have issues to consider when deciding which protocol to use.
Enter eXtensible Markup Language or XML. XML data is stored in plain text. It’s both human and machine-readable and is hardware-independent, making XML data very portable. Using an XML API, you can easily share XML data across different applications, browsers, or operating systems. The XML API receives data from a database, then converts it into XML format to be sent to another application that accepts XML inputs. This effectively allows you to treat your database as if it were structured in XML.
An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build or use such a connection or interface is called an API specification. A computer system that meets this standard is said to implement or expose an API. The term API may refer either to the specification or to the implementation.
In contrast to a user interface, which connects a computer to a person, an application programming interface connects computers or pieces of software to each other. It is not intended to be used directly by a person (the end user) other than a computer programmer who is incorporating it into the software. An API is often made up of different parts which act as tools or services that are available to the programmer. A program or a programmer that uses one of these parts is said to call that portion of the API. The calls that make up the API are also known as subroutines, methods, requests, or endpoints. An API specification defines these calls, meaning that it explains how to use or implement them.
One purpose of APIs is to hide the internal details of how a system works, exposing only those parts a programmer will find useful and keeping them consistent even if the internal details later change. An API may be custom-built for a particular pair of systems, or it may be a shared standard allowing interoperability among many systems.