Both SOAP and REST provides an efficient means of communication through exchange of data between two applications using web services. Although both are unique in their approach, they score over each other depending upon their suitability in various use cases.
What is SOAP?
SOAP (Simple Object Access Protocol) is a platform agnostic web communication protocol that uses only XML to exchange data. It adheres to strict message structure of Envelop, Header, Body and Fault (error) that enhances security and uses http to communicate between different applications.
What is REST?
REST (Representational State Transfer) is an architectural style to exchange data through efficient utilization of resources accessed using a unique URI. REST rides on HTTP/HTTPS to exchange data and supports XML, HTML, plain text and JSON data for API requests and responses.
SOAP Vs REST – Which One to Select
Both SOAP and REST have their own architectural styles that are flexible, scalable, and fulfil varying project requirements leveraging various capabilities offered by them. The following factors can help in selecting a particular approach:
SOAP API is resource intensive due to the heavy XML based message structure payload that consumes large bandwidth. The XML format also makes SOAP protocol slow in processing. On the other hand, REST uses a simple architectural style to transmit data over HTTP making it lightweight and consumes less bandwidth. REST supports various data formats like HTTP, JSON, etc which are easy and faster to parse.
SOAP employs advanced secured protocols like WS-Security that ensures high-level of encryption and security for the transactions/data upholding data integrity, privacy and security. REST API also uses advanced secured protocols like Https along with secured socket layer (SSL) for data security and integrity.
Transfer Protocol Support
SOAP supports various high-level and low-level transport protocols like HTTP, TCP, SMTP, FTP and more to transfer data over internet. Wide spectrum of transport protocol support helps in improving security, speed, security etc. However, REST primarily relies on HTTP/HTTPS to exchange data over internet.
Build In Error handling
SOAP has built-in successful /retrying logic that ensures that if the request fails, the client-side developer gets an XML message with error code and its explanation. This facilitates in faster error resolution and development process. REST does not provide efficient error handling capability with client side developer receiving only error code with no explanation.
Stateless and Stateful
SOAP supports both stateless and stateful operations. Primarily, SOAP is used for stateful operation that involves security and complexity. While, REST is designed for stateless operations.
REST supports caching on HTTP whereas SOAP requires additional configuration to cache information at client-side.
SOAP Vs REST – Applicability in Different Scenarios
Capabilities of REST and SOAP can be leveraged depending on scenarios and requirements.
Banking, Billing and Financial Transactions
SOAP extensively supports security protocols like WS-Security and ACID compliance enhancing transaction security and ensuring robust message encryption this is vital in financial transactions. Normally, these transactions require establishment of strict contracts between Server and Client API that can be clearly defined within a WSDL document avoiding any deviation from standard procedure.
Public API development
Since REST is a stateless operation employing GET, PUT, POST and DELETE to perform tasks, it is easier for the client API to consume it. REST is not concerned about the client side implementation of the API thus offering immense flexibility and scalability.
Extensive Interchange of Messages
REST can be efficiently used in processes where there is extensive interchange of messages such mobile or web applications. REST allows retrying logic in case of major disruption in the service.
Selecting a particular approach between SOAP and REST depends on myriad of factors like development environment, project resources, project requirements and programming language. SOAP is still suited for financial transaction due to its robust security protocols, while REST is most sought after approach for modern day web applications that requires flexibility, scalability and faster processing.