REST (Representational state transfer) and SOAP (Simple Object Access Protocol) are two ways of designing software architecture on internet. There might be more, but today I learned that until a decade ago, almost all internet giants used SOAP. While today, REST is the answer to almost everything.
But what’s the difference? In simple terms1, you access a resource (data) in a REST operation and perform an operation in SOAP operation.
For example,
# REST
getUser(User);
# SOAP
switchCategory(User, OldCategory, NewCategory)
I highly recommend this StackOverflow answer2 for better (and correct) insight.