SOAP vs REST

SOAP is a protocol, while REST is an architectural style. This creates significant differences in how SOAP APIs and REST APIs behave.

Flexibility

SOAP APIs are rigid and only allow XML messaging between applications. The application server also has to maintain the state of each client. This means it has to remember all previous requests when processing a new request.

REST is more flexible and allows applications to transfer data as plain text, HTML, XML, and JSON. REST is also stateless, so the REST API treats every new request independently of previous requests.

Performance

SOAP messages are larger and more complex, which makes them slower to transmit and process. This can increase page load times.

REST is faster and more efficient than SOAP due to the smaller message sizes of REST. REST responses are also cacheable, so the server can store frequently accessed data in a cache for even shorter page load times.

Scalability

The SOAP protocol requires applications to store the state between requests, which increases bandwidth and memory requirements. As a result, it makes applications expensive and challenging to scale.

Unlike SOAP, REST permits stateless and layered architecture, which makes it more scalable. For example, the application server can pass the request to other servers or allow an intermediary (like a content delivery network) to handle it.