Application programming interfaces (APIs) allow different software systems to communicate with each other. Two of the most common types of APIs are REST (Representational State Transfer) and SOAP (Simple Object Access Protocol). Though they have some overlaps, there are key differences between REST and SOAP when it comes to architecture, data formats, verbs, performance, and use cases.
Architectural Style
REST APIs adhere to specific architecture principles centered around resources, while SOAP is simply a messaging protocol that can be implemented in different ways. REST APIs access discrete resources using URLs, while SOAP APIs expose operations rather than resources.
Data Format
REST uses simpler data formats like JSON and XML, while SOAP only works with XML. This makes REST more lightweight and faster than SOAP. Parsing XML has more overhead than JSON.
Verbs
REST leverages HTTP verbs like GET, POST, PUT, DELETE to manipulate resources. SOAP relies on XML messaging without native HTTP verbs. SOAP requires more boilerplate code to simulate CRUD operations.
Performance
Since REST embraces a simpler approach using HTTP and JSON, it has performance advantages over the more robust SOAP. REST requires less bandwidth and resources than SOAP, making it better for internet-scale applications.
Use Cases
REST works better for public APIs and web applications exposed to a wider internet audience. SOAP's support for more robust security through WS-Security makes it ideal for enterprise applications. SOAP also handles complex operations and business processes better than REST.
In summary, REST provides a faster, more scalable and flexible architecture for internet applications and public APIs. But SOAP offers more rigorous security, ACID compliance, and robust messaging for complex enterprise needs. The choice depends on the specific use case and requirements.
When building APIs, analyze the use cases, data formats needed, security concerns, and expected audience to determine if REST or SOAP is more suitable. Also consider developer experience - REST has a lower learning curve than SOAP. Try to leverage existing standards rather than reinventing the wheel.