SOAP

Simple Object Access Protocol (SOAP) is a message specification for exchanging information between systems and applications. When it comes to application programming interfaces ([[APIs]]), a SOAP API is developed in a more structured and formalized way.

Think of SOAP as being like the national postal service: It provides a reliable and trusted way to send and receive messages between systems (and within enterprise applications). It is older, established, and dependable—but it can be slower than competing architectural styles like [[REST APIs|REST]].

SOAP (also known as Simple Object Access Protocol) is a secure way to build APIs, and it works by encoding data in the [[Extensible Markup Language|XML]] format. REST (Representational State Transfer) APIs are more flexible, and they support data transfer in different formats, including XML, [[HTML]], [[Clear-Text|plain text]], [[JavaScript Object Notation|JSON]]], and more.