What Is a SOAP API? Complete Beginner Guide

SOAP APIs have been around for more than two decades, but they are still widely used in banking, healthcare, telecom, travel, insurance, and enterprise software. If you are learning APIs, you will probably hear more about REST and GraphQL. However, many large organizations still rely on SOAP because it is secure, standardized, and works well for complex systems. What Is a SOAP API? SOAP stands for Simple Object Access Protocol . It is a protocol used for communication between applications over a network. A SOAP API allows one system to send a request to another system using XML, and receive a structured XML response. Unlike REST APIs, which usually exchange JSON, SOAP APIs always use XML and follow a strict format. For example: A banking app can use a SOAP API to transfer money. A travel website can use a SOAP API to check flight availability. A healthcare system can use a SOAP API to fetch patient records securely. SOAP was originally created so different systems, written in different