| REST stands for REpresentational State Transfer. | SOAP stands for Simple Object Access Protocol. |
| REST is not a protocol but an architectural style. | SOAP is a XML based messaging protocol. |
| REST does not enforces message format as XML or JSON or etc. | SOAP is XML based message protocol. |
| There is no specification for REST. | SOAP has a standard specification. |
| REST uses (generally) URI and methods like (GET, PUT, POST, DELETE) to expose resources. | SOAP uses interfaces and named operations to expose business logic. |
| Assumes a point-to-point communication model–not usable for distributed computing environment where message may go through one or more intermediaries. | Designed to handle distributed computing environments. |
| Unlike SOAP, REST does not has dedicated concepts for each of these. REST predominantly relies on HTTPS. | SOAP has a set of standard specifications. WS-Security is the specification for security in the implementation. It is a detailed standard providing rules for security in application implementation. Like this we have separate specifications for messaging, transactions, etc. |
| No constraints on the payload. | Payload must comply with the SOAP schema. |
