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Learn about the difference between REST vs SOAP and when to use which Type of API.

Learn about the difference between REST vs SOAP and when to use which Type of API.


Luke Stephens

Luke Stephens

Luke Stephens


When developing web services, choosing the right communication protocol is crucial. Below is a comparison of REST and SOAP, highlighting their core differences:

  1. Protocol Standards: REST can be protocol-agnostic, meaning it can use various protocols such as HTTP, URL, MIME, etc. SOAP, on the other hand, is a standardized protocol with strict rules and must adhere to SOAP standards.

  2. Data Format: REST is flexible and can handle various data formats including XML, JSON, YAML, and others. SOAP primarily uses XML-based message formatting.

  3. Bandwidth: REST is more efficient and uses less bandwidth. SOAP is more verbose and uses a larger amount of bandwidth.

  4. Transport: REST typically uses HTTP or HTTPS for transport. SOAP can use various transport protocols including HTTP, SMTP, TCP, and more.

  5. Statefulness: REST is stateless by design, meaning each call from client to server is independent. SOAP can be stateful, maintaining state through message exchanges.

  6. Error Handling: REST uses standard HTTP status codes for error handling. SOAP uses detailed SOAP fault codes within the message body for the same purpose.

  7. Security: REST's security is handled by the underlying transport. SOAP has built-in security standards, such as WS-Security.

  8. Performance: Generally, REST performs faster due to less overhead. SOAP can be slower due to larger message sizes.

  9. Complexity: REST is simpler to use and implement. SOAP is more complex due to its extensive protocol standards.

  10. Caching: REST can leverage HTTP caching mechanisms. SOAP typically does not support caching mechanisms.

  11. Discoverability: REST uses a more straightforward approach with URIs for discoverability. SOAP uses service descriptions like WSDL for operations and formats.


Example of REST vs SOAP

A RESTful web service for a library might provide a URL like, and a GET request to this URL would return the details of the book with the ID 12345 in JSON format.

A SOAP web service for the same library could expose a WSDL file (Web Services Description Language) describing a method GetBookDetails that expects a request wrapped in XML, like <GetBookDetails><BookId>12345</BookId></GetBookDetails>. The response would also be in XML.

Example of services that use either REST or SOAP

Here are some examples of services that use either REST or SOAP and why they chose that particular approach:


  • Twitter: Twitter uses REST for their API. They chose REST due to its simplicity, ease in integration with other interfaces, and its ability to scale by decoupling the client and server components.

  • Google Cloud Platform: Google Cloud Platform uses RESTful APIs for most of their services, including Google Cloud Storage and Google Compute Engine. REST allows for a more flexible and scalable architecture, which is crucial for their vast number of users.


  • Microsoft Exchange Server: Microsoft Exchange Server uses SOAP for its Web Services. The decision to use SOAP was based on its ability to provide robust messaging patterns, support for transactions, and extensibility features.

  • PayPal: PayPal uses SOAP for their API due to its built-in error handling mechanism, standard protocol, and the ability to automate processes using web services description language (WSDL).

Choosing REST or SOAP

Use REST when:

  • You need a stateless architecture.

  • The bandwidth and resources are limited, making lightweight data formats like JSON preferable.

  • You want to leverage existing HTTP infrastructure.

Use SOAP when:

  • The application requires high security, transactional reliability, and ACID (Atomicity, Consistency, Isolation, Durability) compliance.

  • There is a need for formal contracts and standards (like financial services).

  • Integration with enterprise-level tools and platforms is required.

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