Comparing SOAP vs REST APIs

Although SOAP and RESTful Web Services – both serve the same purpose i.e. building applications based on SOA (Service-Oriented Architecture), yet they are pretty much different in the way how they help in achieving the final output. Let’s note down the most noticeable differences between SOAP and REST based APIs:

SOAP is a XML based messaging protocol
REST is not a protocol but an architectural style
SOAP has specifications for stateful implementation
REST follows only stateless model
Minimal tooling/middleware is necessary. Only HTTP (mostly it’s HTTP based) support is required
URL typically references the resource being accessed/deleted/updated
Well defined mechanism for describing the interface e.g. WSDL+XSD, WS-Policy
Formal description standards not in widespread use. Everybody interprets on his own
Payload must comply with the SOAP schema
No constraints on the payload
Built-in error handling
No error handling though you can use HTTP error codes
Both SMTP and HTTP are valid application layer protocols used as Transport for SOAP
Tied to the HTTP transport model
SOAP web services totally ignore web caching mechanism
RESTful web service take full advantage of web caching mechanism because they are basically URL based
Hard to learn
Easy to learn because everybody understand HTTP
SOAP security is well standardized through WS-SECURITY
Security is provided on the HTTP protocol layer such as basic authentication and communication encryption through TLS
When you’re publishing an API to the outside world that is either complex or likely to change, SOAP will be more useful
Other than that, REST is usually the better option

Feel free to add more differences if you know them. It will help others as well.

Happy Learning !!

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1 thought on “Comparing SOAP vs REST APIs”

  1. 1. SOAP Envelop makes it heavier.
    2. SOAP Support stateless/statefull conversation.
    3. SOAP Support ACI transaction – WS-AT
    4. SOAP Support Reliable Messaging – WS-RM
    5. With reliable messaging async messaging is possible.


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